SALÓN AZUL
09:00 - 09:50
Plenary Review Talk
Invited Speaker:
Karín Menéndez-Delmestre
- Observatorio do Valongo
(Brasil)
[cv]
Karín Menéndez-Delmestre
Observatorio do Valongo
Curriculum Vitae:
Born and raised in Puerto Rico, Karín obtained her B.Sc. in Physics from McGill University in Montreal, Canada. She was a Fulbright Fellow for a year at the Leiden Sterrewacht (Astronomy Institute) in the Netherlands, after which she moved to California to do her PhD in Astronomy at the California Institute of Technology (Caltech). Afterwards, she spent 3 years as a postdoctoral fellow with the support from the Astronomy & Astrophysics National Science Foundation Postdoctoral Fellowship at the Carnegie Observatories, also in California. Since 2011 she is a professor at the Valongo Observatory of the Federal University of Rio de Janeiro. In 2015 she was awarded the “L’Oréal UNESCO ABC Award for Women in Science” in the area of Physics. She is today very proud to be recognized as a “Cientista de Nosso Estado” by Rio de Janeiro’s research funding agency. Her research interests cover a wide range of topics in Extragalactic Astrophysics, with emphasis on formation and evolution of galaxies. Her main interests are: panchromatic study of extreme galaxies in young and distant universe; indirect study of typical galaxies in the distant universe by identifying analog populations in the nearby universe; and the characterization of stellar structures (e.g., spiral arms, bars, bulges) present in local galaxies. Mother of two young daughters, an ambassador of the Brazilian “Parent in Science” movement and current coordinator of her university’s Working Group on Parenting and Gender Equity, she also devotes great energies towards a more inclusive and diverse scientific community.
Chair: Verónica Motta
#556 |
Stellar Structures in Galaxies: Insights from the Local Universe
Karín Menéndez-Delmestre
1
1 - Valongo Observatory, Federal University of Rio de Janeiro.
Resumen:
Galaxies in the local universe are a fossil record of events in the distant universe and present critical constraints on the physical processes underlying the formation and evolution of galaxies. Understanding the variety in properties of galaxies today is thus key to unveiling how galaxies form and transform across cosmic time. We have been plunging into deep imaging of nearby galaxies to get a careful mapping of where stellar mass is concentrated in galaxies. Galaxies present a myriad of distinct stellar structures. We focus on structures that typically characterise local galaxies — such as bulges, disks, bars, and spiral arms — with the intention of building a present-day benchmark to understand the different agents that dictate when and where stars form and through which processes (giant galaxy collisions, interactions with smaller galaxies, etc.). We have also recently launched a long-term observing program to produce the deepest mapping of galaxies accessible from the Southern Hemisphere, complementing the exquisite work that has been performed in the north. I will show a number of discoveries we have made and give you a preview of the exciting work we are doing with our nascent southern survey.
09:50 - 10:20
Plenary Target Talk
Invited Speaker:
Jaime Forero Romero
- Universidad de los Andes
(Colombia)
[cv]
Jaime Forero Romero
Universidad de los Andes
Curriculum Vitae:
Jaime E. Forero Romero es un astrofísico y profesor de física en la Universidad de los Andes en Colombia. Su investigación se centra en la formación de galaxias y la cosmología. Actualmente, se dedica principalmente al apoyo del mapeo del universo a través del Dark Energy Spectroscopic Instrument (DESI), una colaboración internacional que estudia la energía oscura y su impacto en la estructura a gran escala. Desde 2008, ha sido un impulsor activo del Congreso Colombiano de Astronomía y Astrofísica, promoviendo el intercambio académico en su país y la región. En 2016, contribuyó a fundar y coordinar la Oficina Regional Andina de Astronomía para el Desarrollo, apoyada por la Unión Astronómica Internacional. También es un entusiasta divulgador de la astronomía y ha colaborado con artistas para explorar las conexiones entre el arte, la historia y la astrofísica.
Chair: Verónica Motta
#601 |
Mapping the Universe with galaxies: Astronomy, Cosmology, and Artificial Intelligence
Jaime Forero Romero
1
1 - Universidad de Los Andes.
Resumen:
In this presentation, I will discuss recent advances at the intersection of astronomy, cosmology, and artificial intelligence, with the goal of extracting valuable insights from the cosmic web. These advances have the promise of enhancing our understanding of galaxy evolution and refining our knowledge of cosmological parameters. I will start by showing how we observe, measure, and characterize the cosmic web, highlighting their significance in the study of galaxy formation and cosmology. As an illustrative example, I will showcase the Dark Energy Spectroscopic Instrument (DESI), a Stage-IV spectroscopic survey currently constructing the most comprehensive 3D map of the universe. To conclude, I will introduce Graph Machine Learning as a potential tool for extending our comprehension of 3D galaxy maps, enabling deeper exploration of galaxy evolution and cosmology.
10:20 - 10:50
Plenary Target Talk
Invited Speaker:
Alejandra Melo
- Max Planck Institute for Astrophysics, Garching
(Germany)
[cv]
Alejandra Melo
Max Planck Institute for Astrophysics, Garching
Curriculum Vitae:
I am Alejandra Melo, I got my PhD in Astrophysics at Universidad de Valparaiso, Chile, and now I am a postdoc at the Max Planck Institute for Astrophysics in Garching, Germany. My main research focuses on the study of strong gravitational lensing. Currently, I am interested in using machine learning to find galaxy-galaxy lensed systems for the upcoming surveys of LSST and Euclid. I also study the inner structure of gravitationally lensed quasars, obtaining their black hole mass, and the study of microlensing in the images of the lens system.
Chair: Verónica Motta
#602 |
Strong-lens search through deep learning with both ground- and space-based imaging data
Alejandra Melo
1
1 - Max Planck Institute for Astrophysics.
Resumen:
Lensed supernovae are ideal to investigate the supernova progenitor systems and for cosmological studies such as measuring the Hubble constant H0. To measure H0 with percent-level precision, the combination of multiple systems is needed, as already done with galaxy-quasar systems by the H0LICOW and TDCOSMO collaborations. While so far most lensed supernovae were detected only by chance and not through a dedicated search, dedicated effort is required for a sample that allows a combination of measurements. Since detecting these peculiar lenses through the supernova brightness often leads to small image separation systems with unresolved images that have too short time delays for measuring the Hubble constant, we present an alternative approach carried out within the HOLISMOKES collaboration. We use all detected transients to cross-match with all known static lenses on a daily basis. For this procedure, dedicated and efficient lens search projects are a crucial step.
I will introduce our ongoing search for gravitationally lensed transients using deep learning, where I have combined ground-based and space-based imaging using the Hubble Space Telescope (HST) and Legacy survey data, simulating Euclid and the Vera C. Rubin Observatory (LSST). I will present the steps and the different deep learning architectures that have been tested, and also summarize efforts from the whole community.
10:50 - 11:30
COFFEE BREAK
Coffee and Poster Group II setup
11:30 - 13:15
J: Galaxies and Cosmology
Galaxy structure and dynamics
Chair: Horacio Dottori
#212 |
Modelling the dark matter distribution in Milky Way analog galaxies
Natanael de Oliveira
1
;
Karín Menéndez-Delmestre
1
;
Thiago Gonçalves
1
;
Nicolás Garavito-Camargo
2
;
Luis Queiroga-Nuñez
3
;
Marco Grossi
1
1 - Valongo Observatory, UFRJ.
2 - Flatiron Institute.
3 - Florida Institute of Technology.
Resumen:
Our current understanding is that dark matter (DM) accounts for 85\% of the total matter in the Universe. However, its presence, thus far, is only manifested through gravitational effects, where one of its strongest evidence can be observed from the rotation curves (RCs) of disk galaxies. Despite great efforts devoted to the direct and indirect detection of DM, its nature still eludes us. Realistic models of the spatial distribution of DM within galaxies are still scarce and estimating the local DM density (i.e., at $\sim$8~kpc from the Galaxy’s centre) remains a challenge, as currently these estimates rely on significant assumptions regarding the Milky-Way's DM halo. Motivated in understanding the spatial distribution of DM in galaxies like our own, we have undertaken the detailed mapping of DM in a sample of MW analogs. Our sample is derived from the combination of the following surveys: S$^4$G (mid-IR), and both VIVA and THINGS (radio). The mid-IR imaging provided by S$^4$G is the best single-band tracer of stellar mass. The data cubes from VIVA and THINGS allow us to use the dynamics of atomic hydrogen (HI) as a means to isolate and map the DM distribution. The final sample comprises 7 galaxies, selected based on the maximum HI velocity ($v_{max}$=200--280~km~s$^{-1}$) and morphological type (Sab--Sbc) in order to target systems resembling the MW. We construct RCs for the sample using $^{3D}$Barolo, a dynamical three-dimensional modelling software. By using a MCMC-based approach, we develop an analytical model to decompose the RCs into their different components (stars, gas, and DM), enabling us to construct DM radial profiles of our sample. By employing this independent and innovative approach, we obtain a new window of values for the local DM density ($\rho$~=~0.24-0.39~GeV~cm$^{-1}$) that provides tighter constraints but is still consistent with more traditional approaches found in the literature.
#498 |
A SPLASH of Kicked Up Disk Stars in the PHAT Halo of M31
Ivanna Escala
1
1 - Princeton.
Resumen:
The Milky Way (MW) is the cornerstone of our understanding of disk galaxy formation. However, there is growing evidence that the MW’s relatively quiescent formation history sets it apart from its sister galaxy, Andromeda (M31). At the nexus of near- and far-field galaxy evolution, M31 provides an exquisite opportunity to expand our knowledge of hierarchical galaxy assembly and galactic chemodynamics. Outstanding questions remain concerning M31's structural assembly: has its disk survived a major merger within the last few billion years, and does this merger coincide with the formation of its Giant Stellar Stream? In this talk, I will present novel results on the nature of M31's inner stellar halo and disk based on data from the Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo (SPLASH) and Panchromatic Hubble Andromeda Treasury (PHAT) surveys. With measurements for over 3500 individual red giant branch stars, this represents the first large-scale chemodynamical analysis of M31's inner disk region. I will discuss evidence in favor of (1) an inextricable connection between the formation of M31's inner stellar halo and disk, (2) distinct channels driving the formation of the stellar halo along the major versus minor axes, and (3) a uniformly thick structure for the disk.
#012 |
Orbital Structure Evolution in Self-Consistent N-body Simulations
Ivanio Puerari
1
;
Leonardo Chaves-Velasquez
2
;
Diego Valencia-Enriquez
3
1 - INAOE.
2 - IRyA.
3 - Universidad Mariana.
Resumen:
We analyze the orbital structure on three different stellar disk N-body models embedded in a live dark matter halo. During the models evolution, disks naturally form a bar that buckles out of the galactic plane at different ages of the galaxy evolution generating boxy, X, peanut and/or elongated shapes. We evaluate the orbital evolution using the frequencies analysis on phase space coordinates for all disk particles at different time intervals. We analyze the face-on, edge-on, and end-on views morphology of the 2:1 family which is populated in our models as the bar potential evolves. The disk-dominated model develops an internal boxy structure after the first Gyr of the model evolution. Afterwards, the outer part of the disk evolves to a peanut shape which lasts till the end of the simulation. The intermediary model develops the boxy structure only after 2 Gyr of evolution. The peanut shape appears around 2 Gyr later and evolve slowly. The halo-dominated model develops the boxy structure much later, around 3 Gyr and the peanut morphology is just incipient at the end of the simulation (7 Gyr).
#224 |
Properties of disks and spheroids in the Illustris-TNG and EAGLE simulations
Valeria Aylén Cristiani
1
;
Mario Abadi
1
1 - IATE - OAC.
Resumen:
Galaxies are complex stellar systems formed by several overlapping stellar components (bulge, disk, bar, etc.) whose formation and evolution process is inherently related to the individual processes undergone by each of them. We study the properties of discs and spheroids by applying two dynamical decomposition methods to a sample of galaxies with stellar masses $> 10^{10} M_\odot$ identified in the EAGLE and IllustrisTNG cosmological numerical simulations. In agreement with observational results, we find that the stellar mass fraction in the spheroidal component fsph increases systematically with galaxy stellar mass $M_*$ from fractions of $50\%$ for galaxies of $M_* \sim 10^{10} M_\odot$ to $90\%$ for $M_* \sim 10^{12} M_\odot$, although with a fair amount of scatter. For galaxies with stellar masses similar to that of the Milky Way ($M_* \sim 10^{10.6} M_\odot$) and applying isolation criteria we find $f_{sph} \sim 0.2$ at best which is only slightly higher than the lowest values estimated observationally for local galaxies $f_{sph} \sim 0.15$. This would indicate that the cosmological volume simulations are capable of reproducing a population of disk galaxies comparable to those observed. In addition, we perform the extension and analysis of the scaling relations between mass, specific angular momentum and characteristic velocity of disks and spheroids and how they compare with those of full galaxies and those obtained observationally, such as the Tully-Fisher and Faber-Jackson relations. In addition, the dimensionless spin parameter of the halo and the stellar components are analyzed, finding that there seems to be no correlation between them. These results show how closely the formation and evolution history of the galaxy is linked to that of each of its components.
#124 |
Dynamical Analysis of Galaxy Populations in Clusters
Greique Ademir Valk
1
;
Sandro Barboza Rembold
1
1 - Federal University of Santa Maria.
Resumen:
In this work, we analyze the dynamics of galaxy populations in clusters in order to study the impact of the orbital profile on galaxy evolution. Using an ensemble cluster composed of 10,974 galaxies belonging to 143 clusters with line-of-sight gaussian velocity distributions, we obtain the spatial and velocity distributions for four classes of galaxies separated with respect to the main ionizing source of the gas, namely star-forming (SF), transition (T), quiescent (Q) and AGN. The MAMPOSSt code was used to get the mass profile of the ensemble cluster and the velocity anisotropy profile $\beta(r)$ of the galaxy populations. We also perform an inversion of the Jeans equations to obtain the $\beta(r)$ profile, using the mass profile from MAMPOSSt, in a non-parametric way. We find that all populations show similar anisotropy profiles, with more isotropic orbits near the center and increasingly radial orbits with the projected radial distance. Among the galaxy populations, the Q population exhibits the smallest spatial scattering and the lowest velocity dispersions, with the latter being well recovered by the $\beta(r)$ profile from MAMPOSSt. In contrast, SF galaxies, followed by those in the T population, display the highest spatial scatterings and velocity dispersions. While MAMPOSSt could not provide equilibrium solutions for the SF population that reproduce the line-of-sight velocity dispersion profile, a good agreement was obtained for the T class. AGN host galaxies show similar dispersions to those of the T population, but they are found closer to the central region. Equilibrium solutions were obtained for the AGN population, but with higher uncertainties. Our results suggest that environmental mechanisms affect infalling SF galaxies, transforming them into a quiescent population as they thermalize in their parent cluster. In this scenario, the T population can be interpreted as a more virialized SF population with AGN activity induced by the environment.
#105 |
Investigating the extraplanar components in isolated late-type edge-on galaxies.
Minerva M. Sardaneta
1
;
Philippe Amram
2
;
Roberto Rampazzo
3
;
Margarita Rosado
1
;
Monica Sanchez-Cruces
1
;
Isaura Fuentes-Carrera
4
;
Soumavo Ghosh
5
1 - Instituto de Astronomía, UNAM.
2 - Aix Marseille Univ, CNRS, CNES, LAM.
3 - INAF-Osservatorio Astrofisico di Asiago.
4 - Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional.
5 - Max-Planck-Institut für Astronomie.
Resumen:
Some highly inclined ($i\geq80^{\circ}$) late-type galaxies with high star formation rates (SFR) exhibit an extraplanar diffuse ionized gas (eDIG) component, which often extends several kiloparsecs above the galactic disc. Studying the kinematic effects of the eDIG is crucial to understand its interaction with galactic properties. Although several studies using data from integral field units (IFU) spectroscopy have been made, there is currently no conclusive common result on the origin of the eDIG. We selected 14 nearby highly inclined late-type galaxies from the Catalogue of Isolated Galaxies (CIG) to investigate the environmental influences on the eDIG incidence. This sample aims to serve as a baseline for comparison with interacting galaxies, providing insights into the formation and properties of eDIG. We present the H$\alpha$ monochromatic, radial velocity and velocity dispersion maps of galaxies in our sample obtained from observations made with scanning Fabry-Perot (FP) interferometry. To highlight the stellar disc structure, we compare our FP data with near-infrared (NIR) and ultraviolet (UV) images available in the literature. We also compute the H$\alpha$ rotation curves of galaxies in our sample, and we analyse the rotation of the extraplanar component. Preliminary results show that in isolated galaxies the amplitude of the rotational lagging increases with their intrinsic SFR.
#103 |
Associations of dwarf galaxies in a $\Lambda$CDM Universe
Yamila Yaryura
1
;
Mario Abadi
1
1 - Instituto de Astronomía Téorica y Experimental (IATE).
Resumen:
Associations of dwarf galaxies are extended systems composed exclusively of dwarf galaxies, which were identified in the Local Volume for the first time more than thirty years ago. We identify these particular systems using a semi-analytical model of galaxy formation coupled to a dark matter only simulation in the $\Lambda$ Cold Dark Matter cosmological model. Our systems have typical sizes of $\sim 0.2\,{\rm Mpc}\,h^{-1}$ and velocity dispersion of $\sim 30 {\rm km\,s^{-1}}$ in good agreement with observationally detected dwarf galaxy associations. Such large typical sizes suggest that individual members of a given dwarf association reside in different dark matter haloes. Furthermore, associations located in more dense environments present significantly higher velocity dispersion than those located in less dense environments, evidencing that the environment plays a fundamental role in their dynamical properties. However, this connection between velocity dispersion and the environment depends exclusively on whether the systems are gravitational bound or unbound. Although less than a dozen observationally detected associations of dwarf galaxies are currently known, our results are predictions on the eve of forthcoming large surveys of galaxies, which will enable the identification and study of these very particular systems.
13:15 - 13:40
CONFERENCE PHOTO
CONFERENCE PHOTO @ THE BUILDING ENTRANCE (13:15)
18:30 - 19:30
Conferencia Divulgativa
Sede: Planetario de Montevideo. Dr. Gianni Marconi: “El observatorio ALMA: en busca de nuestro origen cosmico”
FOYER
Poster Group I - REMOVAL
Poster Group II - SETUP AND DISPLAY (Wed 10:50 to Fri 17:00)
Poster Group II (Wed - Fri) - A: Fundamental Astronomy
#020 |
The Asymmetric Sunrise Effect on Thales Alleged Measurement of the Sun Angular Size
Jorge Cuadra
1
1 - Universidad Adolfo Ibáñez.
Resumen:
Reports from the 2nd and 3rd Century AD attribute the first measurement of the angular size of the Sun to Thales of Miletus, in the 6th Century BC.
Cleomedes, also in the 2nd Century AD, described a method to perform the measurement, based on timing the duration of the sunrise.
Several modern authors have suggested Thales used Cleomedes' method, but others are skeptical of the connection.
Here I present an objection that has not been discussed in the literature, namely, that the proportionality between the size of the Sun and the duration of sunrise is not constant, but changes with latitude and time of the year, due to what I call the ``asymmetric sunrise effect''.
I show that this effect is large enough to have prevented Thales from obtaining the roughly accurate recorded value.
#232 |
Unsupervised decontamination of field stars in color magnitude diagrams the stars clusters
denis illesca
1
1 - Instituto Interdisciplinario de Ciencias Básicas(CONICET-UNCUYO).
Resumen:
Knowledge of fundamental parameters such as age, metallicity, distance, among others, of
stellar clusters is relevant when it comes to understanding the structure and evolution of galaxies. This is due to
that clusters are excellent tracers of the different subsystems that make up galaxies (bulb, disk,
bar, halo). One of the most powerful tools to study in depth the astrophysical characteristics
of star clusters is the color-magnitude diagram. In the specific case of stellar clusters, their stars
members are distributed in said diagram along sequences that depend on the evolutionary state of the cluster
(age), its metallicity and its distance. In order to carry out a precise astrophysical analysis, it is essential to characterize
and reliably identify the stars that are typical of clusters. In this work we present
a method of decontamination of color-magnitude diagrams of star clusters, developed in Python, which
allows to identify the own stars of the cluster with a statistical assignment of membership for each one
of them.
Poster Group II (Wed - Fri) - B: Surveys, Facilities and Networks
#361 |
Assessing the impact of light pollution on the Uruguayan night sky
Andrea Sosa
1
;
Santiago Roland
1
;
Susana Colmegna
2
;
Keving Mendoza
1
;
Valentina Pezano
1
;
Macarena Risso
2
;
Fabiana Guadalupe
1
1 - CURE - Universidad de la República.
2 - CURE and FADU - Universidad de la República.
Resumen:
Light pollution is the human-made alteration of outdoor light levels from those occurring naturally (DarkSky International - darksky.org), caused by the excessive or inappropriate use of artificial light at night, with a negative impact in the night sky, in biodiversity and in human health. The Milky Way is hidden to more than one-third of humanity (Falchi et al. 2016). Satellite images indicate that light at night increased by a global average of about 2$\%$ per year (Kyba et al. 2017), and in the last decade the brightness of the sky at night increased by an average of 10$\%$ per year (Kyba et al. 2023). \\
We present the first results of a study of light pollution in the night skies of Uruguay, started in the Capital city and the Eastern region at the beginning of 2023. We analized the time evolution of the sky brightness from Unihedron SQM LU-DL and LE measurements taken every 5 minutes during at least 2 months. We also survey illuminance, color temperature, location, design and technology of the outdoor luminaires in each location.\\
The study in Montevideo is financed by the Municipality as part of a project between this institution and our university. The coordination between the Technical Unit of Public Lighting of the Municipality of Montevideo and the astronomy and biology researchers is in charge of Andrés Olivera (FCIEN - UdelaR).
With support from PEDECIBA and the PDU of Physical Sciences of CURE we instaled SQMs at the astronomical observatory, at CURE, and in rural and mountainous areas of Rocha. We are also evaluating these last sites as potential dark sky places where the night sky will be valued as an environmental, scientific, cultural and landscape heritage, and where the darkness of the night sky must be preserved through the regulation of outdoor lighting.
#372 |
Proliferation of Nighttime Artificial Lighting and Light Pollution in Major Urban Areas of Latin America
Kennet J. Rueda Espinosa
1
;
Andres F. Guerrero Guio
2
;
Santiago Vargas Domínguez
2
1 - University of Delaware.
2 - Universidad Nacional de Colombia.
Resumen:
Light pollution is a form of environmental degradation that is increasing worldwide and affects the natural environment, flora, fauna, and various aspects of human life. Despite the growing concern about this issue, its study is still limited in Latin America. In this study, we conducted a comprehensive analysis of the expansion of nighttime artificial light in the major urban centers of Latin America between 2012 and 2022. The study focused on cities including Mexico City, São Paulo, Bogotá, Lima, Santiago de Chile, Buenos Aires, Brasilia, Caracas, San José, Havana, Quito, Asunción, Montevideo, and La Paz.
This study provides valuable information about the growing threat of light pollution in Latin America and supports the need to take measures that help control the associated environmental degradation. Raising awareness about the negative impacts of light pollution on the ecosystem, human health, and astronomical observations is crucial. Implementing lighting regulations, promoting energy-efficient lighting technologies, and incorporating considerations about light pollution in urban planning are essential steps to mitigate the effects of light pollution and protect the natural environment in the major urban centers of Latin America.
#593 |
EVALUATION OF THE IMPACT OF ARTIFICIAL LIGHT AT NIGHT ON THE NOCTURNAL LANDSCAPE AND SOUNDSCAPE OF LAS BRUJAS (CANELONES, URUGUAY)
Florencia Reichmann
1
;
L. Lagaxio
2
;
A. Sosa
3
;
M. Arím
1
;
A. Canavero
1
1 - Departamento de Ecología y Gestión Ambiental. CURE - UdelaR.
2 - Sociedad Civil.
3 - PDU Ciencias Físicas. CURE - Udelar.
Resumen:
Increasing the emission of artificial light at night has well-documented negative effects on the quality of natural dark skyes and changes the natural light/dark cycles, on which many species depend. Dark skies are relevant as natural values and for their cultural and heritage significance. This issue is just beginning to be perceived as a problem by decision makers and the civil society. The present work is a response to the concern of residents of Las Brujas (Canelones, Uruguay) regarding public lighting installation in July 2022. This research analyzes the nocturnal landscape before and after the placement of public lighting and its impact over the natural soundscape. Soundscapes are defined as the set of sounds generated by the elements that compose an environment. Through soundscapes analysis, it is possible to estimate the response of organisms to anthropogenic pressures and to account for the structure and dynamics of the environment. For analyzing the nocturnal landscape, the sky brightness was measured at impact and control sites using an SQM photometer. From measurements obtained at 17 sampling points, sky brightness maps before and after the impact were made. For the analysis of the soundscapes, a Before-After, Control-Impact sampling design was implemented. A passive acoustic monitoring (PAM) was carried out, in which the soundscapes of 5 sites (1 impacted site and 4 control sites) were recorded before and after the implementation of the new public lighting. By performing an analysis of variance, significant differences were found in the sky brightness before and after the public lighting was operational. However, the analyzed acoustic data shows that there are no significant variations in the acoustic landscape despite the alteration of the nocturnal landscape. Hypotheses that can explain this phenomenon are discussed and recommendations for the management of the socio-environmental problem are proposed.
#413 |
Characterizing light pollution in Colombia: all-sky photometry from four sites of astronomical and ecological interest
Juan Pablo Uchima-Tamayo
1
;
Rodolfo Angeloni
2
;
Cristian Goez-Theran
3
;
Marcelo Jaque
1
1 - Universidad de La Serena.
2 - Gemini Observatory, NSFs, NOIRLab.
3 - Oficina de Olimpiadas Colombia, UAN.
Resumen:
Light pollution is an anthropogenic phenomenon that has grown exponentially in recent years due to the improper use of the rapidly evolving lighting technologies. All this unnecessary and misdirected light is causing detrimental effects on astronomy, ecology, human health, among others. The phenomenon is ubiquitous, but not systematic studies have been reported in Colombia, a country with a growing astronomical community and with the highest biodiversity in the world. In this study, we present the first characterization of the quality of Colombian skies from sites of astronomical and ecological interest. Using all-sky photometric data, we obtained the first quantitative estimates of Night Sky Brightness and Correlated Color Temperature from the Tatacoa Desert (the only Starlight Destination in Colombia), the Observatory of the Technological University of Pereira, the Bogotá Botanical Garden and the Guadalupe Hill in Bogotá. Finally, our data were compared with similar sites in Latin America and/or the world. The data also represents an effort to contribute to the protection of the sky, a heritage that we must protect and preserve.
#171 |
Introducing LSST Discovery Alliance Catalyst Fellowship -- Increasing the Transformational Power of Rubin LSST
Andrew Sturner
1
;
Jennifer Sokoloski
2
;
Jarita Holbrook
3
;
Kathryn Johnston
2
;
Beth Willman
1
;
Anissa Tanweer
4
;
Jana Diesner
5
1 - LSST Discovery Alliance.
2 - Columbia University.
3 - University of Edinburgh.
4 - University of Washington.
5 - University of Illinois Urbana Champaign.
Resumen:
In 2021, the LSST Discovery Alliance (LSST-DA; formerly known as the LSST Corporation) launched a unique, cross-disciplinary postdoctoral fellowship to help the scientific community prepare for and make excellent early use of data from Rubin Observatory’s Legacy Survey of Space and Time (LSST). The LSST-DA Catalyst Fellowship funded by the John Templeton Foundation was designed to accelerate ground-breaking scientific discoveries, and to impact the field of astrophysics beyond the research of the Catalyst Fellows. It strives to create and support diverse networks as learning systems that benefit a wide range of participants: Fellows, their advisors, their host departments, teams of mentors, and the broader astrophysics community. Key aspects include: (i) participation of social scientists both as Fellows and on the Steering Committee; (ii) the selection of Fellows committed to producing community impacts beyond the publication of scientific findings and service as ambassadors for the use of Rubin LSST data at their host institutions; (iii) the award of a Fellowship each year to an astrophysicist hosted at an Expansion Site, which is typically a small, under-resourced, or predominantly minority-serving institution currently outside of LSST-DA membership; and (iv) mentoring committees for each Fellow that include the Fellow’s local advisor, an active member of one of the LSST Science Collaborations, a researcher involved in the creation of LSST analysis tools, a faculty member from an Expansion Site, and a social scientist. In the first two years of the Fellowship, LSST-DA recruited 14 Catalyst Fellows – 12 in astrophysics and 2 in the social sciences. This contribution reports on experiences of direct participants – Fellows, Steering Committee members, and mentoring committees – during the development and pilot phases of the Fellowship.
Poster Group II (Wed - Fri) - B: Techniques and Instruments
#447 |
Towards a First Spectro-Photometric Characterization of the Chilean Night Sky
Rodolfo Angeloni
1
;
Juan Pablo Uchima-Tamayo
2
;
Marcelo Jaque
2
;
The Dark Sky Protection Team
3
1 - Gemini Observatory, NSF$^\prime$s, NOIRLab.
2 - Universidad de La Serena.
3 - Gemini Observatory, NSF$^\prime$s, NOIRLab, Universidad de La Serena.
Resumen:
Light pollution is widely recognized as a global problem that, like other forms
of anthropogenic pollution, has significant impacts on ecosystems and adverse
effects on living organisms. In recent years, it has emerged as a fertile field
for interdisciplinary scientific research, socioeconomic studies, and wide-ranging
cultural debates. Chile is widely known for its rich and distinctive ecosystems,
and the superb quality of its northern skies has transformed it into one of the
most important astronomical nodes in the world. Nevertheless, a coordinated
scientific approach to characterize, quantify and monitor the effects of ALAN
on the Chilean sky has started only recently. Our interdisciplinary research
group on ALAN was born five years ago with the explicit purpose of filling
this need, and aims at providing the international community with the first
spectro-photometric characterization of one of the most pristine skies of
planet Earth. Since 2019 we have been regularly monitoring about twenty
distinctive sites across the Coquimbo Region (also known as "Regi\'on Estrella"),
including professional astronomical observatories, astrotourism centers,
natural parks, and metropolitan areas.
In this contribution I will introduce our research group by describing its
raison d$^\prime\hat{e}$tre; stating its short, medium and long-term goals;
and presenting the first results of its surveying campaigns. We further
describe how our scientific projects and outreach initiatives, through a
constant synergy with public and private institutions, contribute to heighten
public awareness about the subtle but devastating effects of light pollution.
Finally, we offer an example where our scientific conclusions have supported
different public committees in taking more enlightened decisions to preserve
the darkness of the Chilean sky, a natural and cultural heritage that is
our scientific, social and moral obligation to defend and preserve.
#476 |
Research and development of sonification tools for astronomical and astrophysic data: the case of sonoUno
Johanna Casado
1
;
Beatriz García
2
1 - Universidad de Mendoza.
2 - CONICET, Universidad Tecnológica Nacional Regional Mendoza.
Resumen:
Data analysis in space sciences has been done exclusively visually for many years, even when there is evidence that more than one sensory style is possible (as is the case of sonification). Maintaining the data analysis exclusively with visual tools not only limits the study of the unknown to the current resolution of the screens but also excludes a group of people who present different degrees of visual impairment. Considering those above and that people with functional diversity experience a large number of barriers to achieving higher education and stable jobs, within the framework of my doctoral thesis, a new modality to access scientific data from space sciences was investigated. SonoUno is a product of this research that makes possible a multisensory display (use of more than one sense) of data files with two or more columns, taking into account the accessibility and inclusion of people with functional diversity from the beginning. Based on the fact that multisensory perception can be a good complement to visual exploration for the understanding of complex scientific data, and the exchange and feedback received from users over six years, sonoUno presents a framework focused on the user and is an application that can be used independently on the computer or through a web page. Additionally, the package presents different scripts for specific sonifications and for use in bash. The work presented here maintains the next fundamental pillars: providing solutions and removing barriers (in education and scientific work, up to now); the use of free programming languages; and the design of infrastructure to improve inclusion.
#130 |
ATLAS-P, the first prototype module of the 2nd generation of ATLAS units: preliminary results.
Javier Licandro
1
;
John Tonry
2
;
Miguel R. Alarcón
1
;
Miquel Serra Ricart
1
;
Larry Denneau
2
1 - Instituto de Astrofísica de Canarias.
2 - Institute of Astronomy, University of Hawaii.
Resumen:
We present the new design of the ATLAS unit (Asteroid Terrestrial-impact Last Alert System to be installed at Teide Observatory (TO) in Tenerife island (Spain), and the results of the ongoing tests of the first module (ATLAS-P). ATLAS-Teide, the 5th ATLAS unit, will be built by the IAC and will be operated as part of the ATLAS network in the framework of an operation and science exploitation agreement between the IAC and the UH. ATLAS is an asteroid impact early warning system developed by the UH and funded by NASA. It consists of four telescopes (Hawaii ×2, Chile and South Africa). Each ATLAS unit maps ¼ of the night sky making 4 observations of each field at hourly intervals, reaching the detection of V=19.5 with the aim of detecting small (~20 m) asteroids in impact trajectories several days before the impact, and a 100 m asteroid several weeks before. In its current setup, an ATLAS unit consist of a 50cm Wright-Schmidt telescope and a CCD camera capable of imaging 30 deg2 in a single shot.
ATLAS-Teide will have a different modular design based on commercial on the shelf (COTS) components. Each module will have an effective diameter of 56 cm, with a 7.3 deg2 field of view and a 1.26 “/pix plate scale. The first prototype module (ATLAS-P) was installed at TO late 2022 with the aim of testing the new design capabilities and to develop all the control and reduction software needed to fully integrate ATLAS-Teide in the ATLAS network. First results obtained with ATLAS-P showing that it fulfill ATLAS requirements allowing to detect asteroids at V=20.2 in 30s exposures are presente and the benefits of the new ATLAS design are discussed in this work.
#572 |
Massive photometric catalogs for S-PLUS: object classification and quasar photometric redshifts
Lilianne Nakazono
1
;
Raquel Ruiz
1
;
Gabriel Perin
2
;
Rafael Izbicki
3
;
Nina Tomita Hirata
2
;
Željko Ivezić
4
;
Claudia Mendes de Oliveira
1
1 - IAG USP.
2 - IME USP.
3 - UFSCar.
4 - UW.
Resumen:
The S-PLUS DR4 contains photometric observations for an area of $\sim$ 3000 deg$^2$ of the southern sky. The optical filter system consists of 5 SDSS-like broad bands and 7 narrow bands centered in stellar features. Here we will describe the machine learning strategies and performance metrics for the star/quasar/galaxy classification (Nakazono et al. 2021) and the estimation of quasar photometric redshifts (Nakazono \\& Ruiz et al. in preparation). Moreover, we will discuss the importance of the narrow-band information for these tasks. The value-added catalogs that resulted from our work are public and can be broadly used by the astronomical community. We will describe our catalogs in terms of magnitude distribution, photometric redshift distribution, and density maps for different data quality criteria. Information on how to access these photometric catalogs via the S-PLUS website (https://splus.cloud), Python (with splusdata package) or TAP queries will also be given.
Poster Group II (Wed - Fri) - C: Astronomy for Development
#318 |
AstroMicro: astronomy arrives in “micro” to television.
Sebastián Ramírez Alegría
1
;
Karla Peña Ramírez
1
;
Julio Carballo-Bello
2
1 - Universidad de Antofagasta.
2 - Universidad de Tarapacá.
Resumen:
In the summer of this year NTV, the educational channel of the Chilean television channel TVN, broadcasted the first six episodes of the show “AstroMicro”. The event was a significant milestone for this interdisciplinary scientific communication project, bringing astronomers, animators, filmmakers, producers, writers, and project managers together.
“AstroMicro”, jointly funded by the TV channel, the Chilean Astronomy Society, and the Chilean Agency for Research and Development (Agencia Chilena de Investigación y Desarrollo), occurs on a “micro” where all the astronomical concepts are revisited with simple but accurate jargon relating the different experiences of the diverse passengers to everyday experiences in a bus. This approach avoids hierarchical communication within the team from the very early stages of the project, fostering communication and avoiding outsourcing the creative components of the product.
In this talk, we will share details of the story behind the production, from the original idea to the screening of the first episodes.
#305 |
Citizen Science on the Fireball detection network: “Bolidos del Cono Sur (BOCOSUR)”
Lucía Velasco
1
;
Valeria Abraham
1
;
Matías Hernández
1
;
Lucas Barrios
1
;
Manuel Caldas
1
;
Gonzalo Tancredi
1
;
Alvaro Guaimare
1
1 - Departamento de Astronomía, Facultad de Ciencias, UdelaR.
Resumen:
We have installed a national fireball detection network consisting of a set of 20 stations covering the entire Uruguayan territory. One of the challenges we face is analyzing the large volume of data generated. For this reason, it has been key to promote a Citizen Science project.
In order to disseminate the BOCOSUR Project, we created a website with general information and a fireball report form. Along with the installation of the stations in high schools throughout the country, we held introductory talks presenting the work related to fireballs. To date, we have given more than 30 talks, reaching a population of over 1000 students.
Furthermore, four virtual training workshops were held for high-school teachers and their students interested in contributing to the analysis of the videos generated by the network.
Each workshop consisted of three meetings. In the first two meetings we focused on presenting the project and introducing the most relevant theoretical concepts. Likewise, we deepen the knowledge about the operation of the stations, and particularly how to manually classify videos. The third meeting aims to put into practice what has been learned about video classification. We have recorded a total of 141 participants enrolled throughout the four editions, of which 105 were students and 36 teachers from over 40 different institutions. Over the course of these editions, 70 participants have successfully completed all the activities. In the last edition more than 1400 videos were analyzed and around 170 meteors were found.
It is of great importance to have a large database of classified videos, not only of fireballs, to train a machine learning classification algorithm that was developed as an Electrical Engineering final project by the AutoBol group (Ballestrino et al. 2022).
Poster Group II (Wed - Fri) - C: Astronomy Teaching and Outreach
#019 |
Protoplanet Express, a Video Game Based on Hydrodynamical Simulations
Jorge Cuadra
1
1 - Universidad Adolfo Ibáñez.
Resumen:
High-resolution observations obtained during the last decade show that protoplanetary discs can be very complex objects. Rather than uniform discs, we see that they have large cavities, spiral arms, rings, gaps, and asymmetries. To understand these features, astrophysicists many times have to develop numerical simulations, in which planets or unseen stellar companions are added to reproduce the observed morphologies. While the spectacular observed images are popular in mainstream media, the simulation side is rarely known by the general public.
We have created "Protoplanet express", a video game in which the user visits different known protoplanetary discs, which are rendered in 3D from actual hydrodynamical simulations. The user will encounter in the models the same features observed with ALMA and other telescopes, and their goal will be to find the reason for each of them. For example, the user completes a level once they find the planet causing an observable gap in the disc.
In this presentation I will show excerpts from the game, discuss its development, release and public reception.
#035 |
Astronomy and Non-Formal Education as promoters of Scientific Literacy: the case of the Rodolpho Caniato Astronomical Pole
Camila Maria Sitko
1
;
Oscar Rodrigues dos Santos
1
;
Michel Corci Batista
1
1 - UTFPR.
Resumen:
Astronomy is one of the Sciences that most causes fascination and curiosity in the general public, and thus, it can be used as a gateway to motivate the interest and participation of students and the general community in the scientific enterprise, thus enhancing the formation of scientifically literate citizens. , capable of making critical decisions about the world around them. As a way of working towards this cause, the use of Non-Formal Education spaces becomes an interesting alternative. In this sense, as a way of exemplifying how this relationship between Astronomy and the formation of scientifically literate citizens occurs, this work presents an overview of the activities and research in teaching carried out within the scope of the Rodolpho Caniato Astronomical Pole, located at UTFPR Campus Campo Mourão, Brazil, to which scientific literacy indicators are associated and discussed.
#036 |
PROPOSAL FOR TEACHING ASTRONOMY IN BRAZILIAN HIGH SCHOOLS BASED ON GAGNÉS LEARNING THEORY
Oscar Rodrigues dos Santos
1
;
Taisy Fernandes Vieira
2
;
Michel Corci Batista
1
;
Marcello Ferreira
3
;
Camila Sitko
1
;
Wladimir Sérgio Braga
1
1 - Federal Technological University of Paraná.
2 - Teacher of Physics in Basic Education - SEED.
3 - University of Brasilia.
Resumen:
This work aimed to evaluate, through mental maps, the potential of an interdisciplinary didactic proposal, in the light of Gagné's learning theory. This was Astronomy teaching in Brazilian high schools. This proposal represents an educational product of the National Professional Master's Degree in Physics Teaching. For Gagné, learning is a change of inner state that manifests itself through behavior change and persistence. The research is based on qualitative research, theoretical assumptions and mental maps were used to constitute the corpus. For the analysis of the constituted data, some of the criteria described by Novak and Gowin (1984) and Buzan (2009) were used as references. The results showed that the students advanced in relation to the hierarchical organization Gagné's intellectual abilities. In addition, they managed to establish interdisciplinary relationships with the Astronomy subjects studied.
#359 |
Hands-on activities for studying light pollution:
photometric measuring of zenith night sky brightness
Lucas Melani Rocha Volpe
1
;
Jane Gregorio-Hetem
1
1 - IAG-USP.
Resumen:
One of the main forms of light pollution is skyglow, which consists of the diffuse light in the atmosphere by artificial origins, causing excessive brightness in the night sky, therefore harming astronomical observations. There are several ways to measure the brightness of the night sky, making it possible to evaluate light pollution levels at a given site. The objective of this work is to present some night sky brightness measuring methods for evaluating and monitoring light pollution levels to elaborate hands-on scholar activities material.
To ensure that the activities can be conducted at schools, allowing the students to perform the data acquisition and analysis, two main methods of night sky brightness measuring were tested: by telescope with coupled CCD camera and by IOS Dark Sky Meter (DSM) app.
Panchromatic cell phone apps are easier to measure, but tend to not produce reliable data when compared to astronomical photometry because of its spectral response in a given filter. Standart results used as reference for evaluating light pollution levels at a site are based on the Johnson V band measurements, so a calibration procedure is necessary to establish comparison between them. As both methods evaluate the brightness of the sky at the zenith, measurements were made with the two apparatus at the same spot and close to the same time.
This procedure allowed to study sky brightness evolution through the night, calculating the averages for each date. In total, 15 observation missions (from April to October 2022) were conducted at the Abrahão de Moraes Observatory (OAM), in Valinhos (SP), where the Argus telescope was used to acquire images in V and B filters. These results were used to produce a tutorial for hands-on activities provided by the “Telescópios na Escola”, an education project based on remote observations with the Argus telescope.
#474 |
QUBIC Observatory: Education, Outreach and Culture connected with the origin of the Universe
Beatriz Garcia
1
1 - CONICET, UTN-FRM.
Resumen:
The link of the human being with the cosmos is ancient. However, the approach to knowing what the universe is like has changed remarkably over time. New projects, with avant-garde instrumentation, are installed in astronomically exceptional regions, where the ancestral culture of native peoples has existed for centuries.
Such is the case of QUBIC (Q-U Bolometric Interferometer for Cosmology), an instrument that aims to detect evidence of the time of universal inflation, installed in November 2022 in the Puna of Salta, land of the Kolla, Kolla del Desierto, Atacamas peoples, among others. At this crossroads between ancestral knowledge and modern science, QUBIC has developed, even before its realization, a link with the local inhabitants and seeks to establish a bridge between both cultures where, in addition, art has its space.
In this presentation we seek to show a possible way to address the issues of education and dissemination of astronomy and astrophysics, maintaining the complex balance between these two cultures, to ensure that local communities take ownership of scientific developments that, without a doubt, contribute to the progress of not only of science, but also of the sites that host them and the local populations
#525 |
A Journey to the Moon: exploring multisensory resources in the teaching and learning of Astronomy
Mariana Ferreira Gomes
1
;
Aires da Conceição Silva
2
;
Silvia Lorenz-Martins
3
;
Priscila Alves Marques
2
1 - Observatório do Valongo.
2 - Instituto Benjamin Constant.
3 - Observatorio do Valongo.
Resumen:
Astronomy education has the potential to inspire students to be engaged in STEAM. However, to achieve this in the classroom is essential to promote equal access to information for everyone. Historically, Astronomy teaching uses mostly visual information and materials as resources. Given this, blind and visually impaired (BVI) students may encounter educational barriers in accessing information, as they need teaching materials adapted to their specific educational needs. Thus, the Universo Acessivel project, located at the Valongo Observatory (UFRJ) in partnership with the Instituto Benjamin Constant, aims to develop didactic resources to improve the teaching and learning process of Astronomy for BVI students. Through topics such as Earth and the Universe, the Brazilian curriculum of Basic education proposes that each student reflects on the characteristics and position of the Earth, celestial objects, and the human species in the Universe. Hence, Astronomy Teaching assumes a primordial function in the student's recognition of its position and role in the Universe. In this work, we intend to present a workbook developed to help teachers and students in the teaching and learning process about the Moon. This stems from the demands identified through qualitative research carried out with Brazilian teachers, which highlighted the challenges in understanding astronomical concepts within the school curriculum. This workbook aims to guide and explore in its potential three resources developed, covering different topics about the Moon: (1) tactile models, (2) a booklet in braille, (3) a talking book. Each resource presents its specificity by engaging students through minds-on, hands-on and hearts-on interactions. Through the experience reports of teachers and students in the evaluation of the material, we expect to discuss the positive impacts of exploring different inclusive resources in the teaching and learning process, allowing a greater integration between students and teachers in the journey of discovery about the Moon.
#075 |
Astronomical outreach activities at the Observatorio Astronómico Los Molinos
Andrea Maciel
1
;
Daniel Fernández
1
;
Alberto Ceretta
1
;
Edgardo Acosta
1
1 - Observatorio Astronómico Los Molinos.
Resumen:
In this poster we present the different outreach activities that take place at the Observatorio Astronómico Los Molinos (from here on, OALM), located at the outskirts of Montevideo, Uruguay. Face-to-face activities, as well as social networks interactions (which have noticeably increased after 2020) will be shown, as a way to take Astronomy and related sciences to as many people as possible.
#111 |
Astropontos: an astronomical news blog in Portuguese
Ingrid Pelisoli
1
1 - University of Warwick.
Resumen:
Understanding a scientific article can be challenging when we are not familiar with the subject. Aiming to facilitate access to the most recent discoveries in astronomy published on astro-ph, the Astropontos blog was created in 2017 by young Brazilian researchers, in partnership with the American blog Astrobites. Astropontos publishes articles in Portuguese, summarising scientific publications using a language that is accessible to undergraduate students, educators and astronomy enthusiasts. Other topics are also occasionally discussed, such as a career in astronomy, astronomical software and discussions about the appreciation of Brazilian science. With ten collaborators, Astropontos has already published over 250 articles and has been accessed in more than a hundred countries, including Portugal, Angola, and Cabo Verde. We are hoping to find new collaborators interested in making astronomy more accessible.
#401 |
Teaching astronomy basic concepts using smartphone sensors.
Martín Monteiro
1
;
Arturo Martí
2
1 - Universidad ORT Uruguay.
2 - Facultad de Ciencias - UdelaR.
Resumen:
Smartphones are computers that, in addition to fitting in the palm of the hand, have the additional advantage of including several sensors that, with the appropriate knowledge, allow these devices to be transformed into very useful and economy portable laboratories for doing and teaching science. In recent years, dozens of experiments have been proposed to teach science and to engage students by allowing them to do science on their own (ref. 1), and in particular as valuable tools to teach astronomy (ref. 2). In this work we show some activities that can be carried out in basic courses of astronomy at high school and university. We show how to perform parallax stellar distance measurements on a scaled system to obtain the distance and the parallactic ellipse (ref. 3). By using the light sensor we show how to measure the light curve of a 3D printed scale asteroid to determine the period and shape factors (ref. 4). We also show how to discover exoplanets by planetary transits in a scaled star system (ref. 5).
\\
\\
References:
\\
1. M. Monteiro and A. C. Martí , "Resource Letter MDS-1: Mobile devices and sensors for physics teaching," American Journal of Physics 90(5), 2022.
\\
2. M. Monteiro and A. C. Marti, "Making sciences with smartphones: The universe in your pocket," Proceedings IAU Symposium No. 367, 2020.
\\
3. M. T. Fitzgerald, D. H. McKinnon, L. Danaia, and S. Woodward (2011), "Using Smartphone Camera Technology to Explore Stellar Parallax,” Astronomy Education Review 10, 010108-1.
\\
4. J. Ziffer, W. Morse, T. Nelson, P. Nakroshis, B. T. Rudnick, M. Brautigam, and W. Parker, "Practicing Spatial Relationship Skills Using an Asteroid 3-D Tool," The Physics Teacher 57, 14 (2019).
\\
5. A. Barrera-Garrido (2015), "Analyzing planetary transits with a smartphone," The Physics Teacher 53, 179.
#507 |
Education and Astronomical Diffusion Activities in Bolivia.
Paola Ochoa
1
1 - NOC NAEC BOLIVIA International Astronomical Union.
Resumen:
The activities of education and dissemination of astronomy in Bolivia, intend to reflect the work done with students, teachers, amateur astronomers, and the general public in the different regions of Bolivia, both in rural and urban areas. sharing the objectives of the IAU, with a public that for the most part is still unaware of this important institution.
work that motivates us to continue growing.
#581 |
Ethnoastronomy of the Curripaco, Piapoco, Puinave, Sikuani and Cubeo ethnic groups
GLORIA MARIA PEÑA IDROBO
1
;
Andrea Milena Navarro Torres
1
1 - Colegio La Primavera- Guainia- Colombia.
Resumen:
In this collaborative research with students from a school in Colombia, we have explored and documented the rich tradition of indigenous astronomy from five ethnic groups: Curripaco, Piapoco, Puinave, Sikuani, and Cubeo. Our main objective was to rescue and preserve the unique astronomical knowledge of these communities, which has been transmitted through oral tradition and is at risk of being lost in the modern era.
Throughout the process, we worked closely with respected members of each ethnic group, who shared with us their ancestral stories related to constellations and cosmos. Through extensive interviews and intercultural dialogues, identified the significant constellations for each ethnic group and documented the stories that accompany them. These stories not only hold astronomical value but are also intricately woven with beliefs, traditions, and ways of life of each community.
Furthermore, we have created a unique star map that depicts the constellations of these ethnic groups, labeling individual stars with their scientific names and their corresponding names in indigenous languages. This map acts as a bridge between ancestral knowledge and contemporary science, enabling a deeper understanding the connections between both perspectives.
One of the most striking findings of our research is how constellations are intricately linked with everyday practices, such as agriculture food. Each ethnic group has developed its own worldview that reflects its natural environment and its relationship with the land and the sky.
Ultimately, our research not only highlights the importance of preserving these valuable traditions but also underscores the richness and diversity of human knowledge about the universe. By sharing these stories and insights with the global astronomy community at this international event, we hope to foster a greater appreciation for the connection between science culture, as well as inspire ongoing efforts to safeguard the voices and perspectives of indigenous communities in modern world.
#541 |
Astronomy and sustainable cultural tourism. A proposal for the construction of the first cultural planetarium in Soacha-Colombia
María Alejandra Patiño Ochoa
1
;
Johan Nicolás Molina Córdoba
2
;
Johana Murcia Rocha
3
1 - Universidad Distrital Francisco José de Caldas, Orbitamautas Astronomy Group.
2 - Observatorio Astronómico Nacional, Universidad Nacional de Colombia; Orbitamautas Astronomy Group.
3 - Orbitamautas Astronomy Group.
Resumen:
Commune VI of Soacha, in the department of Cundinamarca in Colombia, faces challenges that impact its population. In areas like Altos de la Florida, tourist attractions exist that could help alleviate the difficulties affecting its residents, most of whom are families displaced by violence who settled in this area. The main issues affecting this community include limited access to formal education, social stigmatization, and informal employment. Despite the presence of significant tourist potential in the municipality's hills, where pre-Hispanic Muisca pictograms and figures revered for their ancestral heritage can be found, these issues persist. In this context, there is a drive to promote a positive image through astronomical tourism by developing the first planetarium in Soacha. This initiative aims to foster respect for nature and awe for the stars. It will promote education, benefiting future generations and enhancing educational quality through programs that have been implemented as part of the development of a culture centered around astronomy. The planetarium project will not only enrich the infrastructure as the municipality's first planetarium but will also provide astronomy training to the community. The primary goal is to educate the community in this science, leveraging the nonprofit group's expertise in scientific outreach, which has worked with schools, conferences, and astronomy research groups. The planetarium will complement this effort and promote science through astronomy in areas with rich indigenous traditions and other culturally significant elements. Ultimately, this social integration work for the appropriation of scientific knowledge could serve as an example for different regions in Latin America facing similar issues and identified by their often undiscovered cultural richness.
#579 |
Asteroid District: Extending citizen science from Bogotá - Colombia.
Edilberto Suárez-Torres
1
;
César Ayala-Rincón
1
;
Daniel Alejandro Alejandro
2
1 - Universidad Distrital - Observatorio Astronómico.
2 - UPTC.
Resumen:
The Astronomical Observatory "LatitUD" of the Faculty of Engineering of the Universidad Distrital, has organized since 2021 under the title Asteroid District more than 15 asteroid search campaigns framed in "The International Astronomical Search Collaboration"; Asteroid District has allowed more than 1200 people among children, youth, adults, amateurs and astronomy scholars, to participate in the search and preliminary discoveries of main belt asteroids and trans-Neptunian objects; this research shows the statistical results to date, highlighting the potential of these campaigns in the social appropriation of knowledge and scientific procedures.
Asteroid District has grown not only in the number of people involved, but also in the integration of activities oriented to teaching, didactic innovation in astronomy and geospatial data management. This makes it important to show to the academic community the results of the trainings and projections carried out in institutions of different levels of education, where the search for asteroids has been taken as a didactic strategy that develops complex thinking and systemic vision of exact and natural sciences, allowing conceptual approaches to mathematics, physics, chemistry, biology and even social questioning, so that this initiative is constituted as a socio-scientific issue that has been addressed from activities such as: Planetary defense exercises, Astro-capsule, observation races using the GPS of Smartphones, impact simulations with Sandbox, didactic exercises with augmented reality, the asteroid festival, among others.
This presentation shows the didactic activities carried out, their potential, tensions and prospects, seeking to encourage citizen science developed specifically from astronomy, as an axis for the construction of critical thinking, for informed decision making, the development of scientific vocations and the learning of science. In this way, the importance of learning from non-formal educational scenarios and the inter-institutional collaboration of the University, the Observatory, schools and the Office of Astronomy for Education Colombia becomes evident.
#233 |
Una experiencia didactica en el estudio del movimiento propio de las ´
estrellas en el aula
Rafael Girola Schneider
1
1 - Universidad Nacional de Tres de Febrero.
Resumen:
The proper motion of the stars is a very important topic in an Astronomy course.
In principle, it allows us to measure the space velocity of the stars in relation to the Sun and, based on it,
determine distances and other stellar parameters, allowing to probe the vicinity of the solar neighborhood and
the speed of local stars in the galaxy. That is why a work carried out in the teaching staff is presented.
in Physics in the subject of Astronomy II from the “H´ector Medici” Institute (Argentina). The work unifies a historical look
how and what was interpreted in the year 1718 when Edmund Halley found that the stars Sirius, Arthur and
Aldebar'an moved in the firmament more than half a degree since the observations made by Hipparcos,
together with a didactic sequence. That is, where students, through actions, link their knowledge
and previous experiences, with some question that comes from reality and with information about an object of
knowledge, managing to differentiate the improper movements of the stars, in which the stellar coordinates
are affected to the same extent by the movement of precession, nutation and aberration of light, deducing
that only the proper motion corresponds to the real motion of the stars. One of the examples that
it has been put in evidence in the class, it is the proper movement is Barnard's Star moving 10.2 00/
year. One of the tools on which the work is based is the information from the Tycho catalogue, as well as
measurements made by the Hipparcos and Gaia satellites
Poster Group II (Wed - Fri) - C: Heritage and Astronomy Networks
335, 375, 449, 530, 339
#335 |
RECA: Promoting career development opportunities in astronomy to students of Colombian institutions
Natalia Oliveros Gomez
1
;
RECA Collaboration
2
1 - Universidad de Guanajuato.
2 - RECA Collaboration.
Resumen:
The Network of Colombian Astronomy Students (RECA) is a student-lead association formed in 2014. It seeks to support the astronomy student community with the aim of: 1) Connecting the astronomical community with the main goal of supporting early career astronomers in Colombia, and 2) overcome systematic barriers in academia and research. Early career and senior Colombian astronomers conform this collaborative community, and its operation is based on a structure composed of 6 nodes designed to address specific needs of the community. In this talk, we will highlight the work from 3 nodes.
The RECA education program works with schools from all regions of Colombia, providing tools and interaction with Colombian professional astronomers, using virtual chats, connection to remote observations in large telescopes, or personal counseling.
The RECA mentoring program connects undergraduate students with astronomers in advanced career stages. They have personalized tutoring one-on-one, for career advice and guidance for applying to graduate programs in astronomy.
Furthermore, the RECA summer internship program provides the opportunity for Colombian undergraduates to participate in astronomy research projects led by professional astronomers around the globe.
All the programs are running their third version, and their successes have been seen with the positive impact of synergies within the Colombian student population of all academic levels. Funding for some programs has been obtained from national and international entities. The work of the RECA nodes highlights the importance of a student-led community both in connecting the astronomical community, and supporting beginning astronomers. Which in turn strengthens the national scientific development in astronomy. In this talk, we will encourage the Latin American community to create similar networks in other countries to support the next generation of astronomers in the region.
#375 |
The scientific contributions of the first modern Colombian astronomer
Freddy Moreno Cárdenas
1
;
Santiago Vargas Domínguez
2
1 - Gimnasio Campestre.
2 - Universidad Nacional de Colombia.
Resumen:
The astronomical interest within the current territory of Colombia has its roots in the Botanical Expedition of the New Kingdom of Granada, a scientific and exploratory venture led by the Spanish Crown in the late 18th century. This expedition, which aimed to study the natural resources and biodiversity of the region, also fostered the development of scientific disciplines, including astronomy. As part of the expedition's efforts, the creation of an astronomical observatory was proposed to support systematic observations and meteorological studies. In 1803, the observatory was established in Bogotá, making it the first of its kind in the New World. Its primary objective was to record celestial events, measure the positions of stars and planets, and gather meteorological data for better understanding weather patterns in the region. The observatory's early years were marked by the exceptional leadership of Francisco José de Caldas, a polymath who not only excelled in astronomy but also made significant contributions to botany and other scientific fields. Unfortunately, Caldas's life and work were cut short in 1816 when he was executed for his involvement in the Colombian independence movement.
After Caldas's untimely death, the observatory experienced a period of decline, with fewer major astronomical observations taking place. However, in the mid-19th century, a resurgence in astronomical research took place under the leadership of José María González Benito. As the main reactivator of the National Astronomical Observatory of Colombia, González Benito played a crucial role in revitalizing the institution and promoting scientific inquiry in the country. Despite his immense contributions, José María González Benito's name and accomplishments have faded somewhat from the annals of history. In this conference, we aim to shed light on his remarkable legacy and bring attention to the significant role he played in the history of astronomy in Latin America.
#449 |
The Manuel Foster Observatory - History, Science and New Life of the First Professional Observatory in Chile
Thomas H. Puzia
1
;
Pablo Lara
1
;
Simón Ángel
1
1 - Pontificia Universidad Católica de Chile.
Resumen:
The history of the Manuel Foster Astronomical Observatory, affiliated with the Pontificia Universidad Católica de Chile and situated in the heart of Santiago's Metropolitan Park, presents a prime opportunity to promote astronomy and natural sciences to the general public. Established in 1903, the observatory stands as one of the oldest in the Southern hemisphere. At the forefront of cutting-edge research in the early 20th century, it was designated a Historical Monument in 2010, and since then, it has garnered increasing attention from the public. Given the vast number of tourists who annually visit San Cristóbal Hill in Santiago, the Foster Observatory has undoubtedly become an essential stop on their journey. In this talk we will highlight the scientific achievements, infrastructure and the recent transformation and repurposing of the Foster Observatory into an astronomical museum and outreach center. Our goal is to highlight, preserve, and educate using its unique and original historical assets. We will showcase our experience from our weekly diurnal and nocturnal observations that pave the way for a regular visitor program, primarily targeting students from educational institutions across the region, country and continent.
#530 |
Bridging Astronomical heritage and society in a science museum: Historical Scientific Instruments as a tool to preserve our history
Mariana Ferreira Gomes
1
;
Juliana Vilaça Fonseca
1
;
Douglas Falcão Silva
1
1 - Museu de Astronomia e Ciências Afins.
Resumen:
Building bridges between the society and historic scientific instruments (HSIs) belonging to a museum collection is a challenging task, due to the different historical and sociocultural backgrounds involved in the construction of the Brazilian society. Creating a good environment that encourages dialogues about heritage and the learning of the history of national Astronomy through these artifacts requires the use of methodologies that foster the connection between the public and the objects.
In this work, we aim to share some of the educational practices developed and applied using the astronomical artifacts from the collection of the Museum of Astronomy and Related Sciences (MAST), exploring not only their role in the history, or the pedagogical dimensions but also its role in the process of construction of society, promoting dialogues and critical reflections on scientific culture.
Through activities such as mediated guided visits, the project follows four main pillars: (1) models and modeling, (2) three-way interactivity (hands-on, minds-on, hearts-on), (3) museum education, and (4) horizontal teaching and learning. These aspects promoted the exploration of the HSIs from the collection that played an essential role in the development of Brazilian Astronomy, giving them a new meaning that transcends the walls of an exhibition. Using them as a powerful tool to bridge Astronomical heritage and the society, it is possible to expand the socio-pedagogical dimension of the collection, promoting the process of identifying the public, since our memories, culture, and history as a society they are also intangible heritage to be preserved.
#339 |
The 0 Meridian of Buenos Aires
Daniel Carpintero
1
;
Rosa Orellana
2
1 - Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata - Instituto de Astrofísica de La Plata.
2 - Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata.
Resumen:
The Buenos Aires meridian was used at the end of the 19th century as a reference origin to establish limits between the provinces and the then national territories. However, the exact position that this meridian materialized could never be established, with the consequent uncertainty in the limits that depended on it. In this work, we determine for the first time the exact position of the meridian of origin in Buenos Aires.
Poster Group II (Wed - Fri) - D: Fundamental Physics
#347 |
Impact of the matching formalism in hybrid stars and their oscillation modes
Martin Oscar Canullan Pascual
1
;
Mauro Mariani
1
;
Ignacio Ranea Sandoval
1
;
Milva Gabriela Orsaria
1
1 - Facultad de Ciencias Astronomicas y Geofisicas, Grupo de Astrofísica de Remanentes Compactos, Universidad Nacional de La Plata.
Resumen:
Neutron stars reach densities several times higher than nuclear atomic density in their interiors. This causes their cores to be in a state of matter that is impossible to reproduce in terrestrial laboratories. A phase transition between hadronic matter and pure quark matter is expected to occur within these objects, giving rise to hybrid stars. We build the hybrid equation of state by considering a crust equation of state which is added to the outer core of these compact objects using a new thermodynamically consistent formalism. This new way of "gluing" two equations of state will be compared with the classical one, which does not consider the causal and thermodynamic consistency. Then, using the relativistic hydrostatic equilibrium TOV equations, we will obtain the mass-radius relationship for our stellar objects, in order to compare them with the existing observational constraints of neutron stars. In addition, we investigate possible changes that the new matching formalism can cause in the frequencies of the oscillation modes of these hybrid stars.
#499 |
How Far Can You Go With the Mean Free Path Approximation?
Nathan Leigh
1
1 - Universidad de Concepcion.
Resumen:
The mean free path (MFP) approximation is a simple but popular analytic model that describes the rate at which objects collide in dense environments. In this contribution, we aim to quantify the validity of the MFP approximation by confronting analytic theory with numerical simulations. We focus on stellar collisions in dense astrophysical environments as our case study, varying the number of interacting particles from the low- (i.e., N = 3, 4, 5, ...) to high-particle (i.e., N > 100) number limits and exploring a range of particle masses and radii. Our results illustrate that the MFP approximation performs very well for the considerable parameter space explored in this work, with the simulated and theoretical predictions typically agreeing to with a factor of two or better.
#591 |
Asteroseismology using quadrupolar f-modes revisited: Breaking of universal relationships in the slow hadron-quark conversion scenario
Ignacio Ranea-Sandoval
1
;
Mauro Mariani
1
;
Marcos Celi
1
;
M. Camila Rodríguez
1
;
Lucas Tonetto
2
1 - Universidad Nacional de La Plata.
2 - Sapienza University of Rome.
Resumen:
In the context of multi-messenger neutron star astronomy, we explore the frequency and damping time of the fundamental f-mode, responsible for most of the gravitational wave energy, of compact objects, considering a range of model-independent hybrid equations of state. We analyze the impact of the slow conversion of hadrons to quarks, leading to slow and stable hybrid stars. We also study the validity of universal relationships when slow and stable hybrid stars are considered. The latter, potentially limits the applicability of asteroseismology methods in estimating the properties of pulsating compact objects.
Poster Group II (Wed - Fri) - D: Gamma ray sources and cosmic rays
#294 |
The microquasar SS 433 as a cosmic-ray source
Gastón Escobar
1
;
Leonardo Pellizza
2
;
Lautaro Carvalho
2
1 - University of Padova.
2 - Instituto de Astronomía y Física del Espacio, CONICET–UBA.
Resumen:
It has been proposed that microquasars may contribute significantly to the galactic CR population, because their non-thermal emission indicates the existence of efficient particle acceleration mechanisms in their jets. Relativistic hadronic content has been observed in some jets, such as those of the microquasar SS 433. In these cases, the production of relativistic neutrons is an inescapable consequence of hadronic interactions. Given that neutrons are not magnetically confined, they escape from the jet and decay, providing a way for charged particles to escape the system, becoming CRs. In this poster we will show the predictions of our model on neutron-driven CR production applied to SS 433, which is a microquasar accreting in a super-Eddington regime, with highly collimated and powerful jets, which renders this source as an excellent candidate for high CR prodution, according to previous results. We will show our preliminary results on the possible scenarios that could explain the observed non-thermal emission of SS 433, the properties of the CRs produced by neutron escape, and discuss the observability of their emission in the surrounding environment of the microquasar.
#365 |
Studying supernovae associated with long gamma-ray bursts and X-ray flashes.
Lili Michelle Román Aguilar
1
;
Melina Cecilia Bersten
2
;
Maria Manuela Saez
3
1 - Facultad de Ciencias Astronómicas y Geofísicas, UNLP.
2 - Instituto de Astrofísica de La Plata, CONICET.
3 - Department of Physics, University of California, Berkeley.
Resumen:
The origin of stellar explosions associated with long-duration gamma ray bursts (GRB SNe) is a very interesting open topic in stellar astrophysics of massive stars. In all cases, these supernovae (SNe) were classified as type Ic, that is hydrogen- and helium-deficient, showing broad lines in their spectra. This characteristic is indicative of high velocities and energies, and the objects are referred to as SNe Ic-BL. However, there is a number of SNe Ic-BL that have not a GRB observed, which leads to the question of whether it is due to a physical difference or to an observational bias. The aim of this work is to analyze in depth this association and to identify the properties that represent these objects. To this end, we have re-analyzed a sample of GRB SNe previously modeled by our group. The main reason for doing this is that our previous studies used bolometric luminosities calculated using different methods, which prevents comparisons between the objects. Therefore, we have homogenized the calculation method and included new objects to our sample. Then, we modeled the objects using a hydrodynamic code and derived its physical parameters. To conclude, we have compared our results with those obtained for stripped-envelope SNe and SNe Ic- BL that have not been associated to GRB available in the literature. Our findings indicate that more massive progenitor with larger compact remnants consistent with black hole formation are required to reproduce the observations for our sample of GRB SNe.
#402 |
A review of the current state of research on extragalactic sources that emit gamma rays in
the TeV range, using the Cherenkov technique.
Clara Charlotte Valdez López
1
1 - Universidad Mayor de San Andres.
Resumen:
High energy astronomy constitutes a fundamental field of study in astrophysics, which
is in charge of the study of astroparticles, such as gamma rays, which originate in the
natural sources of the universe, through the interaction of cosmic radiation with the
natural particle accelerator that the cosmos possesses.
High-energy gamma rays in the teraelectronvolt (TeV) range are an astrophysical
phenomenon of great interest that provide a unique look at the most violent and
energetic events in the universe. These events occur in various astronomical objects,
such as active galactic nuclei, supernova remnants, pulsars, among others, generating
processes such as the collision of particles at high speeds, the acceleration of particles
in intense magnetic fields, or the disintegration of subatomic particles.
The detection and study of these astroparticles is a technical challenge due to their high
energy and low detection rate. However, thanks to advances in instrumentation and
observing techniques, such as the air and water Cherenkov telescopes, precise
measurements and detailed information on these emissions have been achieved. This is
a unique window to study the most energetic and extreme events in the universe.
Poster Group II (Wed - Fri) - D: High energy phenomenae
#023 |
First results of the glitching pulsars monitoring program at the Argentine
Institute of Radioastronomy
Ezequiel Zubieta
1
1 - Instituto Argentino de Radioastronomía.
Resumen:
Pulsars have exceptionally stable rotation. However, their high rotational stability can be disturbed by glitches, a phenomenon that involves a sudden increase in their rotation frequency, the cause of which is not fully understood. Since 2018, the PuMA collaboration has been using the antennas of the Argentine Institute of Radio Astronomy (IAR) to monitor a group of bright pulsars with high cadence in the southern hemisphere that have previously exhibited glitches. In this work, we report the detection and characterization, through the pulsar timing technique, of: i) two glitches in PSR J1048-5832, which turned out to be the smallest among the 7 glitches previously reported for this pulsar; ii) the most recent glitch in the Vela pulsar; iii) a glitch in PSR J0742-2822, the largest observed in this pulsar to date, and iv) a glitch in PSR J1740-3015.
#241 |
Analyzing the length of the slow stable hybrid star branch and its linkage with multi-messenger observations of compact stars
Mauro Mariani
1
;
Milva G. Orsaria
1
;
Leandro Divano
2
;
Ignacio Francisco Ranea Sandoval
1
1 - Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Argentina/Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina.
2 - Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Argentina.
Resumen:
The internal composition of neutron stars, one of the densest astronomical objects in the universe, is still unknown. Although in the last decade, with the onset of multi-messenger gravitational wave astronomy, several astrophysical observations placed strong constraints on these compact objects, there is still a lack of understanding of the dense matter equation of state. In this work, we model neutron stars as hybrid stars -composed of an inner core of quark matter and a mantle of hadronic matter-, considering an abrupt and slow first-order hadron-quark phase transition in their core. We model the hadronic phase with a piecewise polytropic fit, and the inner quark core through a Color Flavor Locked superconducting equation of state, with corrections due to the strong coupling constant, within the framework of the MIT Bag model. In the framework of this abrupt and slow scenario, it is possible to obtain an extended branch of stable stellar configurations. It has been shown that the appearance of such branches could resolve the existing tension between current astrophysical observations. We analyze the behavior of this extended stability branch by quantifying and systematically studying, for the first time, its length, relating this quantity to fundamental properties of the hybrid equation of state. This study allows not only a deeper understanding of the extended stability scenario with slow hadron-quark conversions but could reveal the mystery of the composition of neutron stars and, consequently, clarify the uncertainty about the equation of state of dense matter.
#242 |
$wI$ asteroseismology revisited: universal relationships that include slow stable hybrid stars
Ignacio Francisco Ranea Sandoval
1
;
Mauro Mariani
1
;
Octavio M. Guilera
2
;
Germán Lugones
3
1 - Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata - CONICET.
2 - Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata - IALP-CONICET.
3 - Centro de Ciências Naturais e Humanas, Universidade Federal do ABC.
Resumen:
In this work, we show that, within the slow hadron-quark conversion regime where extended branches of hybrid stars (SSHS) appear, all universal relationships for wI-modes available in the literature do not hold. Moreover, we show newly discovered universal relationships that include SSHS, and present potential astronomical applications of such relationships, showing that, if the frequency and damping time of the fundamental mode are measured, its mass, radius, and dimensionless tidal deformability can be inferred. The errors of such estimates are smaller than a few per cent for the mass and the radius. For the dimensionless tidal deformability, the errors for compact objects with masses greater than 1.4 solar masses are typically less than 100%.
#501 |
Particle Acceleration in the Heliosphere and in Supernova Remnants
Larissa Ribeiro Magalhães
1
;
Reinaldo Santos de Lima
1
;
Maria Victoria del Valle
1
;
Camila Naomi Koshikumo
1
1 - Instituto de Astronomia, Geofísica e Ciências Atmosféricas da Universidade de São Paulo.
Resumen:
Cosmic rays are charged particles that permeate astrophysical environments and possess energies much higher than those of particles in thermal equilibrium in these media. Their origin is one of the key unresolved questions in high-energy astrophysics. It is believed that the majority of galactic cosmic rays (with energies up to ~PeV) are accelerated in shocks produced by the expansion of supernova remnants (SNRs), although this process is not yet fully understood. On the other hand, in the interplanetary medium, particles accelerated to tens of MeV are directly detected in correlation with the presence of shocks. This research aims to develop a one-dimensional model of confinement and injection of energized particles into the heliosphere and apply it to supernova shocks. In this initial stage, we employ modified magnetohydrodynamic (MHD) simulations to include the influence of cosmic rays through diffusion approximation. We simulate the evolution of the spatial distribution of particles injected in the vicinity of shocks based on events detected in the heliosphere. We will also present the evolution of the energy distribution of particles in Particle-In-Cell-MHD simulations. We compare our results with direct particle observations and also with previous models. Additionally, we outline how we intend to apply this model to SNR shocks. The developing model has the potential to contribute to the understanding of the cosmic ray acceleration process, as certain open questions, such as the development of instabilities and turbulence near the shock - and their impact on particle confinement - can be tested in the interplanetary medium, where direct observations are available. In the future, we plan to extend its application to the construction of non-thermal emission models for SNRs.
#521 |
The glitches and timing noise of the Vela pulsar
Cristóbal Espinoza
1
1 - Universidad de Santiago de Chile.
Resumen:
The smooth rotation of the Vela pulsar was interrupted 17 times during the last 50 years by very rapid and significant increments. These events, known as glitches, are thought to be caused by a dynamic interplay between the outer crust of the star and its superfluid interior. Glitch sizes distribute narrowly around two millionths of the rotation rate. Glitch-like events of smaller sizes can be observed but are considerably less frequent. However, very small events, 100 to 1000 times smaller than the glitches, are ubiquitous but exhibit noise-like properties. We present a complete study of the rotational irregularities of the Vela pulsar using observations carried out at the Mount Pleasant Radio Observatory (Hobart, Australia) for over 20 yr. Preliminary results suggest that the small noise-like events correspond to recurrent small variations of the torque acting on the pulsar and not to rapid increments in the rotation rate, thereby implying an exterior origin.
#609 |
A review on the post-merger gravitational waves emitted in binary neutron star mergers
Gabriela Conde-Saavedra
1
;
Odylio Aguiar
1
;
Henrique de Oliveira
2
;
Maximiliano Ujevic
3
1 - Instituto Nacional de Pesquisas Espaciais.
2 - Universidade do Estado do Rio de Janeiro.
3 - Universidade Federal do ABC..
Resumen:
Gravitational waves detected from the inspiral stage of a binary neutron star merger give information about the nature of the initial components such as their masses, spins, radii and tidal deformabilities. Similarly, observations of the post-merger stage would give hints on the characteristics and the evolution of the remnant of these coalescences. Since post-merger observations by earth-based detectors are not available yet, only numerical simulations are used to study this stage. Therefore, we will review the main characteristics of this kind of merger, as well as the results given by the numerical simulations in order to better understand the different outcomes that are produced in these systems and how the final fate is related to the initial components.
Poster Group II (Wed - Fri) - G: Binary evolution and binary systems
#158 |
Discovery of very wide binaries beyond the solar neighborhood
Julio Chanamé
1
1 - Pontificia Universidad Católica de Chile.
Resumen:
Very wide stellar binaries (with semi-major axes of hundreds of AU and larger) are considered useful tracers of the gravitational potential of their host, and were indeed used to place some of the first constraints on the nature of Milky Way halo dark matter in regimes not probed by microlensing. Theoretical work has shown that, if identified in dwarf galaxy hosts, a well-characterized population of wide binaries may be able to reveal with confidence whether the inner dark matter profile of these galaxies is cusped or cored, a question whose answer remains ambiguous for four decades now. However, our current census of wide binaries is restricted to a few kiloparsec distances from the Sun, and not even Gaia has the astrometric precision to identify these objects at the distances of dwarf galaxies by typical means. I will present the results of the few searches attempted so far for wide binaries in stellar systems
beyond the reach of Gaia. These include our discovery and characterization of the population of wide binaries in the Galactic Bulge, at 6-10 kpc from us, and searches in dwarf galaxies at 30 and 80 kpc.
#164 |
Evolution in low mass close binaries with a black hole: the cases of V404 Cyg and V381 Normae
Leandro Bartolomeo Koninckx
1
;
Omar Gustavo Benvenuto
2
;
María Alejandra De Vito
1
1 - Instituto de Astrofísica de La Plata.
2 - Facultad de Ciencias Astronómicas y Geofísicas de La Plata.
Resumen:
When the components of a binary system are close enough, one can fill its Roche lobe and start transferring mass to the companion. These mass transfer episodes affect the whole evolution of the star, being a completely different situation as if it was isolated. In this work, we study two systems with these characteristics, with the particularity that the accreting object is a black hole on both. These systems have been extensively studied in an observational way, allowing us to know their main features such as the orbital period and the masses of the components, among others. With the help of our binary evolution code, we made evolutionary models to obtain a progenitor for each system, considering the initial moment when the star is on the zero-age main sequence and the black hole is already formed. These models allow us not only to study the whole evolution of the donor star of each system but also to make some constraints about the mass transfer episodes, the orbital evolution, and the change of the black hole spin by accretion.
#222 |
“The OWN Survey: What We Can Tell About Massive Binaries After 18 Years of Systematic Observations”
Julia I. Arias
1
;
Roberto Gamen
2
;
Nidia Morrell
3
1 - Universidad de La Serena.
2 - Instituto de Astrofísica de La Plata.
3 - Las Campanas Observatory.
Resumen:
The OWN Survey is a high-resolution spectroscopic survey of Galactic massive stars accessible from the Southern hemisphere. It has been carried out since 2005, using observational facilities in Chile and Argentina. More than two hundred stars of types O and WN have been monitored to assess their multiplicity status through a systematic study of the radial velocities of their spectra. It was found that about two thirds of these objects show radial velocity variations. Fifty new multiple systems have been discovered, and their spectroscopic orbits accurately determined, effectively doubling the volume of knowledge previously existing about massive stars multiplicity. As an additional outcome, the detection of spectroscopic variability in some objects has allowed insights into magnetic fields, circumstellar material and interactions between stellar components. Thanks to the contribution of the OWN Survey, a significant pool of spectroscopic orbits is available for statistical analysis. The distribution of orbital elements (period, eccentricity, and mass ratio) observed in binaries of different luminosity classes has been investigated, leading to some preliminary conclusions regarding the formation and evolution of these systems.
#299 |
Determining masses using apsidal motion in massive close binaries
Gabriel A. Ferrero
1
;
Roberto Gamen
1
;
Omar G. Benvenuto
1
1 - Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata.
Resumen:
Massive stars play a key role in the chemical evolution of the interstellar medium and thus in the metal enrichment of successive generations of stars. They also determine the dynamical and ionization state of the surrounding interstellar medium, and dominate the luminosity of star-forming regions, open clusters, spiral arms and even entire galaxies. They also have a high multiplicity (probably more than 70% of them are binaries), and are the progenitors of neutron stars and black hole binaries, which in turn are responsible for the emission of gravitational waves. However, the fundamental astrophysical parameters of massive stars are still poorly known, the mass being the most needed because of its importance in stellar evolution.
To address these questions, we are carrying out a systematic observational study aimed at shedding light on the fundamental parameters of these stars. In this contribution we present new spectroscopic orbital solutions for several, already known, eccentric massive close binaries, determine the rate of their apsidal motion, and use this phenomenon, together with stellar models, to determine the masses of 14 stars. We compare the obtained masses with those obtained by the traditional eclipsing binary method, demonstrating the viability of the apsidal motion method.
#419 |
Close binary systems: evolution and environment
María Alejandra De Vito
1
;
Omar Gustavo Benvenuto
2
1 - FCAGLP - CONICET.
2 - FCAGLP - CICPBA.
Resumen:
Binary stars are very important in Astronomy. In some cases, it is possible to access, observationally and with good precision, the fundamental parameter that determines the evolution of an isolated star: its mass.
In close binary systems, if close enough to each other, the evolution of the components changes completely compared to what each of them would have had in isolation, because mass loss may occur by Roche lobe overflow.
As examples of objects due to binary evolution, we can cite low-mass helium white dwarfs, type Ia supernova progenitors, cataclysmic variables, the millisecond pulsar recycling model, black widows, and redbacks families, blue stragglers and yellow stragglers. On the other hand, it is within the framework of binary evolution that the formation of pairs of neutron stars and black holes is understood. In these kinds of binaries, under certain conditions, the merge of the components is a source of gravitational waves.
In addition to the two stellar components, in a binary where the accretor is a compact object, there is another fundamental actor: the accretion disk. Accretion disks have been studied for decades. However, the complexity of the physical processes that occur in it means that, when modeling them, we still have a lot to explore.
In this poster, we will make a brief description of the evolution of close binary systems composed of a low-mass normal star and a neutron star, using models obtained from our binary evolution code. Subsequently, we describe the thin disk treatment (“alpha” disc), where it is possible to decouple the vertical from the radial treatment (in this later, the temporal evolution is found). We present our first results and discuss the steps to follow to study the effect of neutron star irradiation on the accretion disk.
#458 |
Characterising the secondary component of the massive binary system HD165246
Cinthya Nazarena Rodriguez
1
;
Gabriel Antonio Ferrero
1
;
Omar Gustavo Benvenuto
1
;
Roberto Gamen
1
;
Nidia Morrell
2
;
Julia Inés Arias
3
;
Tomás Ansín
1
;
Cole Johnston
4
;
Rebeca Higa
1
;
Cristina Putkuri
1
1 - Instituto de Astrofísica de La Plata.
2 - Las Campanas Observatory, Carnegie Observatories.
3 - Departamento de Astronomía, Universidad de La Serena.
4 - Institute of Astronomy, KU Leuven.
Resumen:
We present a new spectrophotometric investigation of the massive binary system HD 165246, based on high-resolution optical spectra obtained by the OWN Survey. HD 165246 is a short-period spectroscopic binary hosting a primary star of spectral type O8 V. Its light curve, as observed by the K2 satellite, reveals it is also an eclipsing system. From 2006 to 2019, the OWN Survey gathered 55 echelle spectra of HD 165246. The analysis of these data led to the detection of spectral lines arising in the secondary component, enabling a comprehensive characterization of the system. Our study yields a period of 4.59276 +/- 0.00006 days, along with absolute masses: Ma = 22.0 +/- 1.0 $M_{\odot}$ and Mb = 3.5 +/- 0.1 $M_{\odot}$, and corresponding radii: Ra = 7.0 +/- 0.1 $R_{\odot}$ and Rb = 2.2 +/- 0.03 $R_{\odot}$ for the primary and secondary components, respectively. The investigation of the evolutionary state of HD 165246, via theoretical models including rotation, suggests an age of 2 Myr for this binary system. Finally, an analysis of the tidal evolution indicates a non-circular orbit and non-synchronous rotation of the stellar components.
#559 |
TESS Survey for Magnetic White Dwarfs in Symbiotic Binaries
Manuel Pichardo Marcano
1
;
Liliana Rivera Sandoval
2
;
Thomas Maccarone
3
;
David Zurek
1
;
Michael Shara
1
;
Jennifer Sokoloski
4
1 - American Museum of Natural History.
2 - The University of Texas Rio Grande Valley.
3 - Texas Tech University.
4 - Columbia University.
Resumen:
Symbiotic stars are a subclass of interacting binary systems where a compact object, typically a white dwarf (WD) or a neutron star, accretes material from an evolved giant. Accretion can occur through two primary mechanisms: wind accretion or Roche lobe overflow. Wind accretion is the dominant mechanism in most symbiotic stars [1,2], but in a small fraction of symbiotic stars, Roche lobe overflow can also occur [3]. Typical orbital periods of symbiotic stars are observed over relatively long timescales ranging from hundreds of days to decades. Shorter time-scale variability is also observed in these systems. This short-term variability in symbiotics is related to the accretion process and the formation of the accretion disk, which is crucial for understanding the evolution of these systems. The detection of periodic modulations in the optical light curves of symbiotic binaries provides evidence for the presence of magnetic white dwarfs, which plays an important role in the accretion process by truncating the accretion disk and regulating the accretion flow. We propose to do a survey with TESS of symbiotic systems to find new candidate magnetic WD in symbiotics.
Poster Group II (Wed - Fri) - G: Stellar structure and evolution
#056 |
Revised distances for blue horizontal-branch stars based on SDSS photometry
Fabrícia Barbosa
1
;
Rafael Santucci
2
;
Silvia Rossi
1
;
Guilherme Limberg
1
1 - Instituto de Astronomia, Geofísica e Ciências Atmosféricas - IAG/USP.
2 - Universidade Federal de Goiás - UFG.
Resumen:
Stars in the helium-burning phase form a horizontal structure on the colour-magnitude diagram, as they exhibit approximately constant luminosities. The so-called “horizontal-branch stars” can then be used as standard candles. In this project, we work with the blue horizontal-branch (BHB) stars, the most metal-poor population in this evolutionary stage, which are excellent objects to explore the outermost regions of the Galaxy. About 5700 BHB stars were found in the sixteenth data release of the Sloan Digital Sky Survey catalogue, selected by photometric and spectroscopic data, and with individual probabilities of being a BHB star assigned based on surface gravity distributions. To determine the photometric distances, we reanalysed the relation for their absolute magnitude using the ugriz system and proposed using the colour $(u - g)_0$, besides $(g - r)_0$, to estimate the distances. These new simpler relations present reasonable improvements over previously available ones, especially for stars beyond $\sim$40 kpc from the Sun. From the distances obtained, inferred ages from evolutionary models, and the kinematic information available for the BHB stars, we aim to explore the streams found in the Galactic halo and learn more about the formation history of the Galaxy.
#058 |
Metallicity and age effects on lithium depletion in solar analogues
Giulia Martos
1
;
Jorge Meléndez
1
;
Anne Rathsam
1
;
Gabriela Carvalho Silva
1
1 - Universidade de São Paulo.
Resumen:
The lithium present in the photospheres of solar-type stars is transported to the inner parts by convection, reaching regions even somewhat below the convection zone, by transport mechanisms not considered in the standard models. In stars with deeper convective zones, this element can reach regions with temperatures sufficient enough to be destroyed, implying in a lower Li content. More metallic stars show a deepening of their convective zones, so they could deplete more Li in comparison with stars of lower metallicity. To verify this effect, it is important to restrict the stellar parameters, and change only the variable of interest, because Li abundances depend on various stellar conditions. This way, we analyzed 108 stars with $\sim$ 1 M$_{\odot}$ and metallicities within a factor of two relative to the Sun, covering the metallicity range -0.3 $\leq$ [Fe/H] $\leq$ +0.3 dex. We employed high resolution (R = 115000) and high signal-to-noise ratio (S/N = 400 - 1000) HARPS spectra and determined the atmospheric parameters using a line-by-line differential analysis and the Li abundance through spectral synthesis. The ages and masses of the whole sample were improved by refining the isochronal method. We found robust anticorrelations between Li abundance and both metallicity and age, with a significance above 10$\sigma$ in both cases. We also found that planet-hosts are systematically Li-depleted, with a significance of 98\%.
#074 |
Precision spectroscopy in stellar astrophysics, the star-planet connection and Galactic archaeology
Jorge Meléndez
1
1 - Instituto de Astronomia, Geofísica e Ciências Atmosféricas - Universidade de São Paulo.
Resumen:
We show the impact of line-by-line differential spectroscopy on the determination of chemical abundances and stellar parameters. For stellar twins, it is possible to achieve a precision of about 0.01 dex in chemical abundances and a high precision in stellar parameters, allowing to obtain precise stellar masses (of the order of 0.01 solar masses) and ages (about 1 Gyr). Different applications are discussed on the planet-star connection (rocky-forming elements, lithium, and thorium, a key element for heating of planetary interiors), stellar astrophysics (Li/Be and stellar interiors, the relation between magnetic activity and abundances, and the long-term evolution of stellar rotation and activity) and Galactic archaeology (chemical homogeneity of open clusters, nucleosynthetic signatures of AGB stars and supernovae).
#088 |
Correlation between the surface faculae to spot ratio coverage and the magnetic field activity in Sun-like stars
Eliana M. Amazo-Gomez
1
;
Arjit S. Banerjee
2
;
Katja Poppenhaeger
1
1 - Leibniz Institute for Astrophysics AIP.
2 - Indian Institute of Science Education and Research.
Resumen:
By characterizing the particular shape generated by facular (M-like shape) or spot (V-like shape) transits recorded in total solar irradiance, we quantified within the solar analogy, whether the stellar surface was dominated by facular or spot regions. Interestingly, we found that Sun-like stars are distributed between three different regimes, spot-dominated, faculae-dominated, and stars in a transition between the two branches. This poses the question of what makes stellar surface faculae or, spot-dominated?.
In order to address this question, we performed an additional spectroscopic and polarimetric analysis of the stellar activity for a sample of solar twin stars and compare these results with the photometric characterization. The entire sample has spectro-polarimetric observations obtained by the NARVAL, ESPaDOnS, and HARPSpol instruments. We estimated activity indicators such as S index \\& Halpha, and the longitudinal magnetic field (|B|) by applying the Least Squares Deconvolution technique (LSD). By implementing the MOOG-code, a Local Thermodynamic Equilibrium~(LTE) stellar line analysis program, we retrieved the stellar lithium abundance, A(Li). We obtained X-ray fluxes from the XMM telescope. As well as recovered precise rotation periods and the faculae to spot ratio (Sf/Ss) by using the GPS method from TESS photometric records. In this work, we present the findings of our photometric and spectroscopic comparison.
#106 |
Is the oldest planetary nebula really a member of the open cluster M37?
Vasiliki Fragkou
1
;
Quentin Parker
2
;
Roberto Vazquez
3
;
Laurence Sabin
3
;
Jackeline Suzett Rechy-Garcia
1
;
Denise R. Gonçalves
1
1 - Valongo Observatory, Federal University of Rio de Janeiro.
2 - The University of Hong Kong.
3 - Universidad Nacional Autónoma de México.
Resumen:
We have found very strong evidence that an extended bipolar planetary nebula (PN), lying in the line-of-sight of the Galactic open cluster M37, is actually its physical member- only the third such instance confirmed in the Galaxy. The rarity of such an association underlies the importance of its detailed study, which combined with our previous data of open cluster PNe provides valuable independent data to the fundamental initial-to-final-mass relation that is vital for stellar evolution studies and the enrichment of both carbon and nitrogen in the Galaxy. We estimated the properties of the PN and of its progenitor from Gaia DR3 cluster color-magnitude diagrams and Padova theoretical isochrone fitting. Among our remarkable results, we emphasize the following: The mass of the progenitor PN star has been found to be around 2.8 Msol. The nebula is huge (having a major axis of 445 arcsec), which implies a kinematical age of around 80x$10^3$ yrs- the oldest ever PN- suggesting that PNe in clusters do not dissipate as fast as field PNe.
#125 |
Metallicity effects on the Age-Chromospheric activity diagram
Gabriela Carvalho Silva
1
;
Jorge Meléndez
1
;
Giulia Martos
1
1 - Universidade de São Paulo.
Resumen:
Age determinations can be very challenging, especially as we go to colder main-sequence stars. An alternative way for estimating ages is to take advantage of the magnetic changes along the stellar evolution. Many efforts have been put into improving the age-chromospheric activity (AC) relations. For instance, the use of solar twin data to study the magnetic evolution of stars similar to the Sun, with iron relative abundances ranging from -0.15 dex to 0.15 dex, show a clear correlation between chromospheric activity and age, in which the activity decreases as the stars age. Previous works have pointed out that the stellar metallicity affects the measurement of activity indexes. In this work, we investigate these effects on the activity proxy, R$^{\prime}_{HK}$ index, derived from Ca II H and K chromospheric emissions in solar-type stars. Thereby, this method can be applicable for stars with parameters beyond solar twins. Our results show that without a metallicity factor, these AC relations could underestimate (overestimate) the ages of metal-poor (-rich). Finally, we propose a multi-parametric AC relation.
#134 |
Exploring the uncertainties in mixing processes of low-mass stars: Preliminary results
Martín Miguel Ocampo
1
;
Marcelo Miguel Miller Bertolami
1
;
Leandro Althaus
1
1 - Instituto de Astrofísica de La Plata, CONICET-UNLP.
Resumen:
Mixing processes are among the least understood physical processes in stellar evolution. Moreover, mixing processes in the structure and evolution of stars has sizeble effects both in the duration of certain evolutionary phases and in the chemical structures that can be proved thorugh asteroseismology. In this talk we will discuss our ongoing studies in the impact of compositionally driven convection and fingering convection in the late evolution of low-mass stars. We will then discuss possible impacts in the asteroseismology of pulsating sdBs, GW Vir and DAVs.
#136 |
The influence of the Zeeman effect on radial velocity variations in solar-type stars
Augusto de Paula Baldo
1
;
Luan Ghezzi Ferreira Pinho
1
;
Raphaelle Haywood
2
1 - UFRJ - Observatório do Valongo.
2 - Exeter University.
Resumen:
One of the greatest goals of astrobiology is to find a planet similar to Earth around a star similar to our Sun. However, accomplishing this feat is a major challenge for the radial velocity method due to instrumental limitations and the need to achieve an accuracy of 10 cm/s in the measurements. These limitations are being overcome by more modern instruments (for example, the ESPRESSO spectrograph), but another obstacle remains: stellar activity. Several phenomena such as sunspots, plages and other magnetic effects can cause variations of up to 100 m/s in the radial velocities of solar-type stars, preventing the detection of signals from planets like Earth. In our work, we seek to improve the radial velocity detection technique by modeling the contributions of one of these phenomena associated with stellar magnetic activity: the Zeeman effect. This effect causes broadening or distortion of spectral line profiles and can have a signature large enough to prevent detection of terrestrial planets. Thus, we investigated the Sun and its characteristics as an ordinary star from images of the Helioseismic and Magnetic Imager (HMI). We used the SolAster code to obtain the Sun's radial velocity and magnetic activity curves over a period of six months. Through a comparison between the two curves, we can infer the contribution of solar activity to radial velocity variations. A next step would be adding, in the algorithm, a function that describes the influence of the Zeeman effect on the solar radial velocity so that we could eventually identify and remove the contribution of this magnetic variable. Therefore, we hope that, from an understanding of the Zeeman effect signal in the Sun, we can extend this analysis to other similar stars, improving the accuracy of the radial velocity method, so that planets with mass similar to Earth can be detected.
#148 |
Massive Stars in Low-Metallicity Environments: Observations vs. Models
Júlia Camões Alves
1
;
Wagner Luiz Ferreira Marcolino
1
1 - Observatório do Valongo - UFRJ.
Resumen:
Massive stars are extremely rare compared to solar-type stars and, their evolutionary paths, are still not well understood. They are progenitors of supernovas, neutron stars, black holes, gamma-ray bursts and are possible future sources of gravitational waves. Therefore, the understanding of their physical properties is a fundamental question for stellar astrophysics.
This project aims to investigate the correlation between the wind's strength with the environment's metallicity. We expect that the winds will be more intense in higher metallicities, as these stars have line-driven winds — driven by the transference of momentum from their UV radiation field to metal lines.
Even though observations agree with the theory for high-luminosity stars, there is no clear correlation in the low-luminosity regime (log L/Lsun < 5.0). Therefore, we will explore the wind-luminosity relation to evaluate the strength of the wind for different metallicity environments, by comparing stars from the Milky Way, the Large Magellanic Cloud, and the Small Magellanic Cloud.
We will use CMFGEN, a stellar atmosphere code that is able to model the spectra of OB stars allowing the determination of the wind's intensity. Our initial sample consists of 11 observed spectra from the Very Large Telescope/X-Shooter Spectrograph and the Hubble Space Telescope COS and STIS spectrographs, obtained from the XShootU collaboration. In our methodology, we (i) estimate the main photospheric parameters by using an algorithm that searches for the best fits to an observed spectrum from a grid of models; (ii) analyze the wind features from the observed UV/HST spectra and (iii) obtain the stellar luminosity from the SED fit.
We will present the model fits to the observed optical and UV spectra from the stars. The physical properties derived from the atmospheric analysis will be discussed in the context of wind strengths at different metallicities and compared with recent literature results.
#153 |
Fine Structure of the Age-Chromospheric Activity Relation in Solar-Type Stars
Paulo Vitor Souza dos Santos
1
;
Gustavo Frederico Porto de Mello
1
;
Diego Lorenzo de Oliveira
2
;
Erica Costa Bhering
1
;
Felipe Almeida Fernandes
3
;
Ignasi Ribas
4
1 - Observatorio do Valongo - UFRJ.
2 - Laboratorio Nacional de Astrofisica.
3 - Universidade de Sao Paulo.
4 - Institut de Ciencies de lEspai.
Resumen:
Spectral lines with strong photospheric absorption are tools from which we can measure emissions from stellar chromospheres. In solar-type stars, these emissions are intrinsically related to the stellar structure: the differential rotation and convective motions are responsible for sustaining magnetic fields, which inject non-thermal energy into the chromosphere. This energy injection monotonically decays with the stellar age, as the star evolves and has its rotation rate slowed down through the angular momentum loss by magnetized stellar winds. The most studied chromospheric activity indicator for solar-type stars are the Ca II H \\& K lines. In this work, we study the H-alpha line and the infrared triplet of Ca II, indicators that usually receive less attention. Through stellar atmospheres models and spectra with good signal-to-noise ratio and moderately high resolution (obtained at Observatorio do Pico dos Dias - LNA), we determined absolute chromospheric fluxes for hundreds of stars of spectral types F, G and K, main sequence dwarfs and subgiants. We determined/compiled precise atmospheric and evolutionary parameters for the sample stars. Comparing the H-alpha and Ca II chromospheric indicators, we showed that metal-rich stars are, in general, more active in H-alpha and substantially inactive in the Ca II chromospheric activity indicators, with that being, possibly, a pure spectral effect, where the high absorption of the Ca II lines in metal-rich stars mimics a quieter chromosphere. By means of an age-activity-mass-metallicity regression, we also showed that the chromospheric flux in H-alpha may be successfully used as a stellar age indicator for stars, at least, slightly older than the Sun. We present new results on the age-activity-mass-metallicity relations for all three spectroscopic chromospheric diagnostics.
#157 |
Dynamos in partially convective M-dwarfs
Bárbara Toro Velásquez
1
;
Petri Käpylä
2
;
Carolina Ortiz Rodriguez
1
;
Felipe Navarrete
3
;
Dominik Schleicher
1
;
Juan Pablo Hidalgo
1
1 - Universidad de Concepción.
2 - Leibniz-Institut für Sonnenphysik (KIS), Schöneckstr. 6.
3 - Nordita, KTH Royal Institute of Technology and Stockholm University.
Resumen:
M-dwarfs are low-mass main-sequence stars, which are the most common type of star in the galaxy. It is well know that they have significant magnetic activity but the mechanism that controls this is still unknown. M-dwarfs with more than 0.35 $M_{\odot}$ are partially convective, and this transition marks an important change in the stellar interior that must affect the production and storage of internal magnetic fields. The aim of this work is to test a new computational model for the dynamo of partially convective M-dwarfs. This model consists of three-dimensional magnetohydrodynamical (MHD) numerical simulations using the "star-in-a-box" model developed by Käpylä (2021) and within this model, we want to change the magnetic boundary condition to see how this can affect the dynamo. Up to now, we can observe that cycles are formed in three of our simulations, while two others present a dynamo that appears to be more diffuse.
#160 |
Core-dynamo simulations of A-type stars
Juan Pablo Hidalgo
1
;
Petri Käpylä
2
;
Carolina Ortiz-Rodriguez
1
;
Felipe Navarrete
3
;
Dominik Schleicher
1
;
Bárbara Toro-Velásquez
1
1 - Universidad de Concepción.
2 - Leibniz-Institut für Sonnenphysik.
3 - Universität Hamburg.
Resumen:
Early-type stars are mostly stably stratified in their interiors, with convective cores due to a steep temperature gradient produced by the CNO cycle. One of the subclasses of these stars are the chemically peculiar Ap and Bp stars, which host large-scale magnetic fields in the order of 200 G to 34 kG. Some of the hypothesis to explain these fields, are the fossil field theory, and the core-dynamo theory. We performed 3D numerical simulations of a $2~M_\odot$ A-type star with a convective core of roughly $20\%$ of the stellar radius surrounded by a radiative envelope, using the star-in-a-box model, as a way to explore magnetic fields driven by convection in the core of the star. The non-ideal compressible magnetohydrodynamics equations were solved using the {\sc Pencil Code}. We explored rotation periods from 8 to 20 days, and these simulations were divided into two sets: The whole star inside a box of side 2.2 times the stellar radius ($R_*$), and a \textit{zoom} set, where the side of the box is $0.6 R_*$. Both sets allow to have a better understanding of the core, studying its dynamo solutions, large-scale flows, differential rotation, and also the magnetism in the surface of the star. We conclude that the core is able to host very strong dynamos. Nevertheless, only a very small fraction of the magnetism can reach the surface, which is not enough to explain the observations.
#169 |
Abundances of Bioessential Elements on Solar-type Stars Using High Resolution Spectra
Ellen Costa-Almeida
1
;
Luan Ghezzi
2
;
Katia Cunha
3
1 - Observatório Nacional.
2 - Universidade Federal do Rio de Janeiro.
3 - University of Arizona.
Resumen:
Since the discovery of the first exoplanet around a solar-type star in 1995, we have witnessed a fast increase in the number of exoplanets detected – surpassing the mark of 5400. These discoveries, associated with an increasingly detailed characterization of exoplanets and their host stars, have expanded the frontiers of Astrobiology and allowed even more comprehensive studies on the formation and habitability of planets and the distribution of life in the Universe. When we think about life as we know it, we are naturally driven to think of the most frequent elements in the composition of organisms: the CHNOPS (carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur). Though they are bioessential elements for life on Earth, they are not widely explored in abundance studies in general due to challenges in their analyses. Thus, for a better understanding of the structures of planets, habitability and life, it is fundamental to have more homogeneous and precise abundances for these elements for a large number of stars. Therefore, in this work, we derived atmospheric parameters and abundances of C, O and S using equivalent widths measured on high-quality spectra and the software MOOG, focusing on solar-type stars with detected exoplanets, in order to investigate the possible relation between these elements and the formation and habitability of planets, to contribute for a better understanding of the necessary conditions for life to emerge. Our homogeneous abundances will also contribute to the expansion and update of the Hypatia Catalog, allowing studies in other areas, such as chemical evolution of the Galaxy. We present results for abundances of Fe, C, O and S for 241 solar-type stars and their relationships to the presence of planets – which are in agreement with the literature –, and oxygen abundances determined by our automated pipeline using spectral synthesis.
#181 |
O Vz stars in low-metallicity environments in the Magellanic Clouds
Leidy Arango
1
;
Julia Arias
1
1 - Universidad de La Serena.
Resumen:
Massive stars are powerful "cosmic engines" that modify the morphology, chemistry and dynamics of their host galaxies, playing a fundamental role in the Universe. They are found in distant and highly extinction regions, so our understanding of their formation and evolution is still limited. The morphological and quantitative study of their optical spectra is a powerful tool for determining their properties. In this work, we focus on stars of the O Vz class, identified by presenting a He II 4686 absorption much stronger than expected (see for example MPG 655 in NGC 346). It has been suggested that these objects are on, or very close to, the Zero-Age Main Sequence (ZAMS), so studying them can provide key information about the massive star formation process.
The "z phenomenon" has been investigated in the Galaxy, but there are no systematic studies in environments with different metallicity. Using high and intermediate-resolution optical spectra obtained at the VLT and LCO observatories (Chile), we are carrying out a comparative study of O Vz stars belonging to two star-forming regions in the Magellanic Clouds: 30 Doradus in the LMC and NGC 346 in the SMC, along with a star-forming region in the Milky Way: NGC 3603. Here, we present the preliminary results of our analysis, which provide clues about the role of metallicity and other parameters in the development of the z spectral feature.
#205 |
Detailed spectroscopic analysis of F G K stars in open clusters and field.
Angela Catalina Franco Becerra
1
;
Orlando Jose Katime Santrich
2
;
Nelson Vera Villamizar
1
1 - Universidad Pedagogica y Tecnologica de Colombia.
2 - Universidade Estadual de Santa Cruz.
Resumen:
Open clusters have been used as a key tool to study the stellar evolution theory and the structure of the Galactic disk.
In this work we have obtained chemical abundances for F G K stars within the enviroments: open clusters and field. The high-resolution spectra were obtained from the ESO/archive, the method to calculate the stellar atmospheric parameters and chemical abundances is based on the LTE-hypothesis, we have
derived homogenus abundances for the elements, Na, Mg, Al, Si, Ca, Cr, Ti, Ni, Y, La, Zr, Ce, and Nd. The derived atmospheric parameters shown that
the stars are in different evolutionary phases as main sequence, sub-giant, and RGB phase.
Our abundances, for clusters and the field, were similar to the other sample homogeneously obtained like GAIA-ESO Survey, GALAH and APOGEE.
Consequently, our spectroscopic analisys is a reliable tool to investigate the stellar evolution procesess that happening in the Galactic disk.
The obtained abundance ratios [Y/Mg], [Y/Al], [Y/Si], [Y/Ca] and [Y/Ti] present tendences with the ages in a similar way to the other homogeneo-
us samples. However, in opposite direction to them, these ratios have higher scattering. Therefore we concluded they should not be considered as spectroscopic age indicators for F G K stars.
#218 |
Asteroseismic catalogue of \textit{Kepler} Red Giants
Francisca Espinoza-Rojas
1
;
Saskia Hekker
1
;
Quentin Coppée
1
;
Jeong Yun Choi
1
1 - Heidelberg Institute for Theoretical Studies (HITS gGmbh).
Resumen:
Recent estimates show that \textit{ Kepler} observed ~32,000 red giants, which are of particular interest since they present oscillation modes probing both their envelopes and stellar cores. Properties of these oscillation modes (frequencies, linewidths and amplitudes), together with stellar modelling and other techniques, can be used to compare stellar evolution theory and observations. Moreover, we can estimate stellar mass, radius, and age using asteroseismic global parameters combined with spectroscopic information.
Current catalogues provide asteroseismic masses and radii for only ~16,000 red giants, and oscillation mode properties for just a third of them. For this reason, we aimed to exploit the full potential of \textit{Kepler} data and used TACO (Tools for the Automated Characterisation of Oscillations), a data-driven code for the extraction of oscillation characteristics, to estimate asteroseismic parameters and mode properties of the ~32,000 Kepler red giants. Here we present our catalogue and how it can contribute to various fields of Astronomy.
#243 |
Chromospheric and Coronal Activity and Its Dependence on Rotation in Praesepe and the Hyades
Alejandro Núñez
1
;
Marcel Agüeros
1
;
Jason Curtis
1
;
Kevin Covey
2
;
Stephanie Douglas
3
;
Stanislav DeLaurentiis
1
;
Jeremy Drake
4
;
Minzhi Wang
1
;
Sabine Chu
5
1 - Columbia University.
2 - Western Washington University.
3 - Lafayette College.
4 - Center for Astrophysics.
5 - Massachusetts Institute of Technology.
Resumen:
Low-mass ($\lesssim 1.2 M_\odot$) main-sequence stars lose angular momentum over time, leading to a decrease in their magnetic activity. The details of this rotation--activity relation between remain poorly understood, however. Using observations of members of the $\approx$700 Myr-old Praesepe and Hyades open clusters, we aim to characterize the rotation--activity relation for different tracers of activity at this age. To complement published data, we obtain new optical spectra for 250 Praesepe stars, new X-ray detections for ten, and new rotation periods for 28. These numbers for Hyads are 131, 18, and 137, respectively. The latter increases the number of Hyads with periods by 50\%. We use these data to measure the fractional $\mathrm{H}\alpha$ and X-ray luminosities, $L_{\mathrm{H}\alpha}$/$L_{\mathrm{bol}}$ and $L_{\mathrm{X}}$/$L_{\mathrm{bol}}$, and to calculate Rossby numbers. We find that at $\approx$700 Myr almost all M dwarfs exhibit $\mathrm{H}\alpha$ emission, with binaries having the same overall color--$\mathrm{H}\alpha$ equivalent width distribution as single stars. In the Rossby--$L_{\mathrm{H}\alpha}$/$L_{\mathrm{bol}}$ plane, unsaturated single stars follow a power-law with index $\beta = -5.9$$\pm$$0.8$ for Rossby $>0.3$. In the Rossby--$L_{\mathrm{X}}$/$L_{\mathrm{bol}}$ plane, we see evidence for supersaturation for single stars with Rossby $\lesssim$ 0.01, following a power-law with index $\beta_\mathrm{sup} = 0.5^{+0.2}_{-0.1}$, supporting the hypothesis that the coronae of these stars are being centrifugally stripped. We find that the critical Rossby value at which activity saturates is smaller for $L_{\mathrm{X}}$/$L_{\mathrm{bol}}$ than for $L_{\mathrm{H}\alpha}$/$L_{\mathrm{bol}}$. Finally, we observe an almost 1:1 relation between $L_{\mathrm{H}\alpha}$/$L_{\mathrm{bol}}$ and $L_{\mathrm{X}}$/$L_{\mathrm{bol}}$, suggesting that both the corona and the chromosphere experience similar magnetic heating.
#252 |
Detailed chemical composition of solar analogues with and without planets
Marilia Carlos
1
;
Anish Amarsi
1
1 - Uppsala University.
Resumen:
The detailed chemical compositions of planet-hosting stars provide vital clues on the formation and composition of exoplanetary systems. A recent analysis by Pavlenko et al. (2019) suggests that planet-hosting stars tend to have larger C/O abundance ratios than stars without confirmed planets at given metallicity. This signature was solidified in Amarsi et al. (2019) via a three dimensional non-local thermodynamic equilibrium (3D NLTE) analysis of about 60 F- and G-dwarfs in the thin disk.
Here, I will present results from a detailed and extended reanalysis of the Amarsi et al. (2019) sample. We take advantage of high resolution and high S/N spectra from HARPS, and correct for departures from 1D LTE where possible, in order to determine Li, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu and Zn abundances with high precision and accuracy. I will contrast the result for stars with and without confirmed planets, and discuss the possible implications on our understanding of exoplanetary systems.
#255 |
Core-Collapse Supernova Progenitors from Light Curves and Stellar-Evolution Models
Melina Bersten
1
1 - IALP-FCAGLP.
Resumen:
Supernovae (SNe) are excellent laboratories for testing many aspects of stellar-evolution theory with strong implications on many various areas of astrophysics. Their light curves are extremely sensitive to the properties of their progenitor stars or systems and their environments. With the increasing amount and improved quality of current data, new types of SNe or unexpected features in normal events are being detected. These discoveries challenge our standard knowledge of how massive stars explode, as well as the mechanisms that power these events. In this talk I will focus on the modelling efforts that we have been doing in order to understand the properties of normal and some peculiar objects. Particularly, I will show our recent results on a large sample of hydrogen-rich SNe. Our analysis indicates that most of the SNe II come from relatively low-mass progenitors (MZAMS < 10 Msun). This results have important implications on our knowledge of massive-star evolution.
#258 |
Determination of Fundamental Parameters of Wolf-Rayet Stars in Eclipsing Binary Systems
Tomás Ansín
1
;
Roberto Gamen
2
1 - Facultad de Ciencias Astronómicas y Geofísicas, UNLP.
2 - Instituto de Astrofísica de La Plata, CONICET-UNLP.
Resumen:
Despite the fundamental importance of massive stars in the Universe, our knowledge of them remains incomplete. One of the most uncertain aspects is related to mass loss, which dramatically influences their evolution after the main sequence, when they become giants, supergiants and/or Wolf-Rayet (WR) stars.
In this study, we present two known massive double-lined spectroscopic binaries, composed of a WR-type component and an O-type component, which we have now discovered as double eclipsing binaries using high-precision photometry from TESS. This confirmation allows us to determine their stellar parameters with good precision. As these eclipses are both photospheric and non-photospheric, we have used two methods: an ad hoc combination of the PHysics Of Eclipsing BinariEs Eclipsing Binary Modeling Software (PHOEBE) with a Thomson scattering treatment to describe the non-photospheric eclipses; and a light curve synthesis algorithm for binaries containing stars with extended expanding atmospheres, which takes account of both types of eclipses.
The combination of high-precision TESS photometry, radial velocity curves, and the consideration of the nature of the eclipses improves the accuracy of our parameter determinations for these eclipsing binaries. The determined masses and radii, mainly for the WR components, are analysed in the context of massive stellar evolution.
#289 |
Unveiling the evolutionary states of B supergiant stars
Julieta Paz Sánchez Arias
1
;
Péter Németh
1
;
Elisson Saldanha da Gama de Almeida
2
;
Matias Agustin Ruiz Diaz
3
;
Michaela Kraus
1
;
Maximiliano Haucke
4
1 - Astronomical Institute of the Czech Academy of Sciences.
2 - Instituto de Física y Astronomía/Universidad de Valparaíso.
3 - Instituto de Astrofísica de La Plata (CONICET-UNLP).
4 - Universidad Nacional Arturo Jauretche.
Resumen:
We analyzed three blue supergiants (BSG) in this study: HD\,42087 (PU\,Gem), HD\,52089 ($\epsilon$\,CMa) and HD\,58350 ($\eta$\,CMa). These stars show pulsations and were suspected to be in an evolutionary stage either preceding or succeding the red supergiant (RSG) stage. We used 2-min cadence TESS data to study the photometric variability and we obtained new spectroscopic observations at the CASLEO observatory (Argentina). We used non-LTE radiative transfer models calculated with the code CMFGEN to derive their stellar and wind parameters. For first time, CMFGEN was coupled with the automatic spectral fitting procedure {\sc XTgrid}. The spectral modeling was limited to changing only the $T_{\rm eff}$ , $\log g$, $\dot{M}$, and CNO abundances. The frequency spectra of all stars show stochastic oscillations and indications of one nonradial strange mode, $f_r=$ 0.09321 d$^{-1}$ in HD\,42087 and a rotational splitting centred in $f_2=$ 0.36366 d$^{-1}$ in HD\,52089. We conclude that the rather short sectoral observing windows of TESS prevent establishing a reliable mode identification of low frequencies connected to mass-loss variabilities. The spectral analysis confirmed gradual changes in the mass-loss rates and our derived CNO abundances are in line with values reported in the literature. We achieved a quantitative match with stellar evolution models for the stellar masses and luminosities. However, the spectroscopic surface abundances turned out to be inconsistent with the predictions from Geneva stellar evolution models. The stars show N enrichment, typical for CNO cycle processed material, but the abundance ratios are not reflecting the associated levels of C and O depletion. We found HD\,42087 (PU\,Gem) to be most consistent with a pre-RSG stage, and HD\,58350 ($\eta$\,CMa) is most likely in a post-RSG stage. We were unable to model HD\,52089 ($\epsilon$\,CMa) with any evolved BSG tracks and conclude its relatively low mass and high luminosity are most consistent with a rejuvenated merger scenario.
#300 |
Atlas of Massive Galactic O-type Spectral Standards in the near-infrared
Federico Giudici Michilini
1
;
Roberto Gamen
1
;
Gabriel A. Ferrero
1
;
Nidia Morrell
2
1 - Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata.
2 - Carnegie Observatories, Las Campanas Observatory.
Resumen:
The study of spectral morphology is a powerful tool for understanding the fundamental properties of stars. The spectral classification scheme for O stars has been revised in the context of the Galactic O-Star Spectroscopic Survey and a new set of spectral standard stars has been proposed. Since the vast majority of the Galactic O stars are visible only in the infrared due to large interstellar absorption in the optical, it is necessary to extend this work towards those wavelengths. We are working on the construction of an atlas of Massive Galactic O-type Spectral Standards in the near-infrared (MaGOSS in the NIR), observing the standards defined in the last installment of the Galactic O-Star Spectroscopic Survey with high-quality spectra in the wavelength range between 0.85 $\mu$m and 2.5 $\mu$m. We used the GNIRS (Gemini Observatory, Hawaii) and FIRE (Las Campanas Observatory, Chile) spectrographs.
We present here an advance of the Atlas of MaGOSS in the NIR, which includes spectra of a sequence of dwarf and supergiant stars. We analyze this data set to establish some spectral characteristics of such stars, with the aim of defining classification criteria in the near-infrared range, such as the ratios between \mbox{He\,{\sc i}} $\lambda$1.700 $\mu$m and \mbox{He\,{\sc ii}} $\lambda$1.042 $\mu$m and between \mbox{He\,{\sc i}} $\lambda$1.700 $\mu$m and \mbox{He\,{\sc ii}} $\lambda$1.692 $\mu$m.
#301 |
Supernova Light Curves with the HSH telescope at CASLEO
Axel Nahuel Méndez Llorca
1
;
Gastón Folatelli
1
;
Laureano Martinez
1
;
Lucía Ferrari
1
;
Keila Ertini
1
1 - Instituto de Astrofísica de La Plata, CONICET–UNLP, Argentina.
Resumen:
Multi-band light curves of supernovae (SNe) provide crucial information about the properties of their progenitor stars and allow to estimate cosmological distances. In recent years, discovery and follow-up efforts focused on obtaining the earliest possible data of SNe because this is critical to study the external structure of the exploding star. Here we present the results of an intensive SN monitoring campaign performed remotely by the SOS (Supernova Observations and Simulations) group using the Helen Sawyer Hogg (HSH) 60 cm telescope at CASLEO, Argentina. The main goals of the campaign were: i) to obtain multi-band BVRI photometry of transients within hours/days from discovery, ii) to follow up selected SNe in order to produce longer-term light curves. During 37 consecutive nights, we monitored 78 recently detected transients. We obtained more than one epoch for 32 of them, and we followed five SNe with more than 10 epochs. This data set allowed us to test the feasibility of performing very early SN follow up with a small telescope in Argentina. In addition, we present the light curves of three Type Ia SNe from our sample, which allowed us to estimate precise (
#323 |
Coronal Mass Ejection Trajectories from Solar-type Stars
Fabian Menezes
1
;
Adriana Valio
1
;
Yuri Netto
2
;
Alexandre Araújo
3
;
Christina Kay
4
;
Merav Opher
5
1 - Centro de Rádio Astronomia e Astrofísica Mackenzie (CRAAM), Universidade Presbiteriana Mackenzie.
2 - Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG), Departamento de Astronomia, Universidade de São Paulo.
3 - Centro de Rádio Astronomia e Astrofísica Mackenzie (CRAAM).
4 - Heliophysics Science Division, NASA Goddard Space Flight Center.
5 - Department of Astronomy, Boston University.
Resumen:
The Sun and other solar-type stars have magnetic fields that permeate their interior and surface, extends through the interplanetary medium, and is the main driver of stellar activity. Stellar magnetic activity affects physical processes and conditions of the interplanetary medium and orbiting planets. Coronal mass ejections (CMEs) are the most impacting of these phenomena in near-Earth space weather, and consist of plasma clouds, with magnetic field, ejected from the solar corona. Precisely predicting the trajectory of CMEs is crucial in determining whether a CME will hit a planet and impact its magnetosphere and atmosphere. Despite the rapid developments in the search for stellar CMEs, their detection is still very incipient. In this work we aim to better understand the propagation of CMEs by analysing the influence of initial parameters on CME trajectories, such as position, velocities, and stellar magnetic field’s configuration. We reconstruct magnetograms for Kepler-63 (KIC 11554435) and Kepler-411 (KIC 11551692) from spot transit mapping, and use a CME deflection model, ForeCAT, to simulate trajectories of hypothetical CMEs launched into the interplanetary medium from Kepler-63 and Kepler-411. We apply the same methodology to the Sun, for comparison. Our results show that in general, deflections and rotations of CMEs decrease with their radial velocity, and increase with ejection latitude. Moreover, magnetic fields stronger than the Sun’s, such as Kepler-63’s, tend to cause greater CME deflections.
#338 |
Project SOL (Solar Origin and Life): Detailed characterization of candidates at ZAMS and Subgiant stages
Carlos Eduardo Oliveira dos Santos
1
;
Luan Ghezzi Ferreira Pinho
1
;
Gustavo Frederico Porto de Mello
1
;
Diego Lorenzo de Oliveira
2
1 - Observatório do Valongo - UFRJ.
2 - Laboratório Nacional de Astrofísica.
Resumen:
The luminosities of the stars vary throughout their evolution, changing the position and extent of their habitable zones. Furthermore, the chromospheric activity of the host star can influence the amount and the type of radiation received by the present planets, possibly altering their habitability. Thereby, the study of stars that are similar to the Sun at different points of its evolutionary trajectory is essential to understand how terrestrial planets can maintain the necessary conditions for the emergence and evolution of life as we know. Therefore, in this work we identified and characterized stars that could represent the Sun at the ZAMS and subgiant stages. Thus, the sample of stars was selected using photometric boxes, which resulted in 8 candidates to represent it at the ZAMS stage and 10 at subgiant stage. We performed the analysis of the candidates using high resolution (R = 35000 - 115000) and signal-to-noise (S/N > 150) spectra obtained with modern instruments on different telescopes around the world. We adopted the classical spectroscopic method, which uses equivalent widths of Fe I and Fe II lines and is based on the excitation and ionization equilibria. Additionally, we derived evolutionary parameters (mass, radius, luminosity and age), using theoretical evolutionary tracks and isochrones, and kinematic parameters for all stars in our sample. We also performed age estimates through 2 additional independent methods and we present the chromospheric activity levels of our candidates. From these, our results show that we successfully identified 3 excellent candidates capable of representing the Sun at the ZAMS (2) and subgiant (1) stages. Moreover, 2 other candidates of our sample could be interesting for studying the Sun with 2 Gyr. These candidates can help us better understand how the properties of Sun-like stars vary over time and their influence on the habitability of possible exoplanets.
#367 |
Measurement of the longitudinal magnetic field component in Herbig AeBe stars using the LSD technique
Daniel Ruiz Basante
1
;
Giovanni Pinzón Estrada
1
;
Julio Ramirez Velez
2
1 - Universidad Nacional de Colombia.
2 - UNAM.
Resumen:
The study focuses on young stars of the Herbig Ae Be type, which are intermediate-mass stars in the pre-main sequence with rotation speeds of around 150 km/s. These stars exhibit high temperature and luminosity with a predominantly radiative internal structure. Around 10 percent of these objects display magnetism, and this property is measured using the spectropolarimetry technique, which observes the splitting of spectral lines to indicate the presence of a magnetic field. The analysis of spectra from the PolarBase database for Herbig Ae Be stars shows a high level of noise in detecting profiles of intensity and circular polarization, which are parameters of Stokes I and V, respectively. To extract the magnetic signal, the LSD technique is employed, allowing for the measurement of the longitudinal component of the magnetic field. To carry out this study, a line profile mask is created in VALD, simulating a spectrum with the temperature, metallicity, microturbulence, and gravity conditions reported in the literature for these objects. Next, the spectra of interest are consulted in PolarBase, and a cross-correlation is performed to obtain profiles in the Doppler space for Stokes I and V, using the calculation equation for the longitudinal component of the magnetic field developed by Donati J.F et al. in 1997. The goal of this work is to achieve an observational study of stellar magnetism and develop a computer tool to measure the field in these types of objects. Understanding the origin of magnetism in these stars is crucial for comprehending their structure and the formation process during the early stages of their lifecycle. Additionally, the importance of determining the values of lambda sub 0 and g0, which influence the value of the magnetic field component. This study is expected to contribute to the knowledge of Herbig Ae Be stars and their magnetic behavior.
#037 |
Magnetic field map of an Ap star: Deep learning applied to the synthesis of polarized Stokes parameters
Julio Ramirez Velez
1
;
Joan Raygoza
2
;
Irvin Lopez Nava
2
1 - UNAM.
2 - CICESE.
Resumen:
Presentamos los resultados de un entrenar una red neuronal que permite obtener los 4 parámetros de Stokes (I,Q,U,V) para distintas líneas espectrales. Más aún, extendemos nuestra estudio al análisis de perfiles multi-línea tipo LSD. Aplicamos nuestra metodología para el mapeo de campos magnético a nivel fotosférico de una estrella químicamente peculiar, HD 24712.
#374 |
Prebiotic molecules identification in young solar-type stellar objects: methanol
Juan José Maldonado Portilla
1
;
Heidy Mayerly Quitian Lara
2
1 - Universidad Industrial de Santander.
2 - University of Kent.
Resumen:
Methanol, a simple alcohol composed of carbon, hydrogen, and oxygen atoms, plays a crucial role in the study of chemistry. The study of methanol is of great importance due to its simple molecular structure and high abundance, which makes it a potential precursor for more complex organic compounds, including amino acids, the building blocks of life.
The goal of this research was to identify the rotational lines of methanol, plot a rotational diagram and determine its abundance in young solar-type stellar objects, namely pre-stellar objects such as Barnard 1, L1527 and NGC 1333 IRAS 4A. And thus gain a better understanding of the abundance of methanol in pre-stellar objects, providing valuable insights into the possible formation processes and chemical environments in which prebiotic molecules arise. For signal acquisition, receivers E090, E150 and E230, connected to a fast Fourier transform spectrometer (FFTS), were used. CASSIS software and the CDMS and JPL databases were used to identify the identities of the spectral lines. All lines detected with intensities greater than 3 SIGMAS were taken into account for the analysis, ensuring a complete investigation of the rotational lines of methanol in the studied objects. Barnard 1 showed 62 lines, L1527 presented 37 lines and NGC 1333 IRAS 4A showed 171 lines. In addition, rotational diagrams were constructed using the identified lines, providing a method to understand the temperature and abundance distribution of methanol along with valuable information on the physical properties and abundance of methanol in Barnard 1, L1527 and NGC 1333 IRAS 4A.
#589 |
The XShootU Stellar Library - hot low metallicity stars
Lucimara Martins
1
;
XshootU Collaboration
2
1 - Universidade Cidade de Sao Paulo.
2 - -.
Resumen:
Stellar spectral libraries are one of the main ingredients of stellar population models, powerful tools in the study of unresolved stellar systems.
They can be either empirical or theoretical. Empirical libraries are based on observations, meaning that all features in models generated with them will be real.
The disadvantage is that it will always be limited by the stars we can observe. Theoretical libraries do not have this setback, since it is possible to generate stellar spectra with any atmospheric parameters desired. However, models are based on approximations and simplifications, therefore not quite yet able to reproduce all features of real stellar spectra. That is why, despite the existence of several empirical libraries, there are still efforts to push their boundaries. One of the major deficiencies of the empirical libraries available today is the coverage of hot$/$young stars and low metallicity. In this work we present the XShootU stellar library, the most recent effort to try to fill this gap. The ULLYSES program devoted 450 HST orbits to create an UV spectroscopic library of 160 massive stars in the LMC
and the SMC. It uniformly samples the parameter space of spectral type and luminosity class for massive OB stars.
In parallel to ULLYSES, XShootU, is collecting high S$/$N spectra with $R\sim10000$ over the spectral range 300 nm to 2.5 microns of these stars. This will vastly extend the power of ULLYSES spectra by merging the UV, optical, and NIR. ULLYSES + XShootU is by far the most complete, highest-S$/$N, and highest
resolution library of hot, massive stars with the broadest spectral coverage. In combination with other stellar libraries available in the literature, XshootU will allow self-consistent population synthesis models of systems hosting both young and old stars.
#597 |
The morpho-kinematic structure of the Thor$^\prime$s Helmet Nebula
Gerardo Ramos-Larios
1
;
J.A. Quino-Mendoza
1
;
E. Santamaría
2
1 - Instituto de Astronomía y Meteorología Dpto. de Física, CUCEI, Universidad de Guadalajara.
2 - Instituto de Radioastronomía y Astrofísica, UNAM.
Resumen:
Around some Wolf-Rayet (WR) stars we found gas and dust whose presence is associated directly with their central star. Often, these material presents patterns and structures in a variety of shapes. In this context, an object with striking features is NGC2359 (Thor$^\prime$s Helmet), whose complex and intricate filamentary sharp structure, is composed of a large shell of gas and dust that surrounds the central star. We present here a morpho-kinematic study of the WR nebula NGC 2359 around the WR7 star through high-resolution Manchester Echelle Spectrograph (MES) observations. A total of 26 long-slit positions were used. We found that our initial Shape model resembles that for a cloud-cloud collision, with a variety of structures and velocities.
#126 |
Exploring variability in B supergiant stars: a theoretical and photometric approach to pulsation modes and detection of binary systems
Aldana Alberici Adam
1
;
Michalis Kourniotis
2
;
Lydia Cidale
1
;
Alejandra Christen
3
;
Wolfgang Glatzel
4
1 - Instituto de Astrofísica de La Plata (IALP) - CONICET.
2 - Astronomical Institute of Czech Academy of Sciences.
3 - Instituto de Estadística, Universidad de Valparaíso.
4 - Institut für Astrophysik, Georg-August-Universität Göttingen.
Resumen:
It is well known that B supergiant stars evolve from O-type stars, however, there is still much uncertainty about their evolution after they leave the main sequence. The asteroseismological study of light curves of dwarf and massive supergiant stars has revealed that they all pulsate in specific modes, defining regions of instability at the top of the HR diagram. Detecting and studying pulsating stars in binary systems is essential for exploring the internal structure of stars and verifying evolutionary models, as they allow the masses of each component to be measured accurately and independently. However, detecting binary systems among evolved B stars is challenging, either because of observational bias or, perhaps, due to the intrinsic variability of the more evolved primary component, leading to light curves and spectra variations.
In order to improve our knowledge of these phenomena, light curves of a sample of massive stars, with L/M ratio > 4, observed with the TESS satellite were studied to determine their periods and quasi-periods, which could be associated with pulsation, binarity, or both. In addition, the pulsation modes were studied on the basis of a linear non-adiabatic model and compared with the observationally detected frequencies, to estimate a theoretical mass for these stars and address the mass discrepancy problem. To obtain a detailed description of the periodic behaviour of the signals, two complementary tools were used: the Lomb-Scargle periodogram and the Weighted Wavelet Z-Transform (WWZ).
Poster Group II (Wed - Fri) - J: AGN
#017 |
Analysis of the impact of broad absorption lines on quasar redshift measurements with synthetic observations
Luz Ángela García
1
1 - Universidad ECCI.
Resumen:
Accurate quasar classifications and redshift measurements are increasingly important to precision cosmology experiments. Broad absorption line (BAL) features are present in 15-20\% of all quasars, and these features can introduce systematic redshift errors, and in extreme cases produce misclassifications. We quantitatively investigate the impact of BAL features on quasar classifications and redshift measurements with synthetic spectra that were designed to match observations by the Dark Energy Spectroscopic Instrument (DESI) survey. Over the course of five years, DESI aims to measure spectra for 40 million galaxies and quasars, including nearly three million quasars. Our synthetic quasar spectra match the signal-to-noise ratio and redshift distributions of the first year of DESI observations, and include the same synthetic quasar spectra both with and without BAL features. We demonstrate that masking the locations of the BAL features decreases the redshift errors by about 1\% and reduces the number of catastrophic redshift errors by about 80\%. We conclude that identifying and masking BAL troughs should be a standard part of the redshift determination step for DESI and other large-scale spectroscopic surveys of quasars.
#077 |
An ALMA view of the host galaxies of Radio-Loud Quasars at z \textgreater 5
Chiara Mazzucchelli
1
;
Roberto Decarli
2
;
Eduardo Banados
3
;
Yanu Khusanova
3
;
Emanuele Paolo Farina
3
;
Sofia Rojas
4
1 - Universidad Diego Portales.
2 - INAF.
3 - MPIA.
4 - IMPRS.
Resumen:
Radio jets in Active Galactic Nuclei (AGN), observed in $\sim10\%$ of such sources at any cosmic time, are thought to play a key role in the black hole (BH) growth and in BH-host galaxy co-evolution. Jets can crucially enhance BH accretion rates, while regulating star formation in the host via the so called "radio-mode feedback". Regardless of its key importance, very little has been known so far about the host galaxy/radio-jets interaction in the very early universe, due to the lack of suitable observations of high-z quasars with powerful radio-emission (radio-loud; RL). Here, we present new ALMA observations of the host galaxies of six RL quasars at $z>5$, $\sim$1 Gyr after the Big Bang, aimed at recovering their dust and $[C II]$ emission line in the rest-frame FIR. We show that these galaxies already host large dust reservoirs and are forming stars at rates $>30 M_\odot/yrs$. We do not observe strong differences in the FIR emission with respect to the hosts of radio-quiet quasars, but we recover a decrease in the $[C II]$ emission line flux, which could be due to a suppression of the cool gas due to jets, or an overestimation of the galaxy FIR dust emission due to a strong contribution of the jet synchrotron radiation. Moreover, we search for signs of mergers and/or potential gas-rich galaxies around these RL quasars, as expected from theoretical predictions. Lastly, we point at future, multi- wavelength follow-up observations, that will play a crucial role in disentangling the key contribution of radio jets in BH-host galaxy co-evolution in the first $Gyr$ of the universe.
#083 |
Probing black hole formation via collisions in black hole clusters
Benjamín Gaete
1
;
Alessandro Lupi
2
;
Michael Fellhauer
1
;
Dominik Schleicher
1
1 - Universidad de Concepcion.
2 - Università di Milano-Bicocca.
Resumen:
The origin of SMBHs in galactic centers at high redshift in the early Universe is still unknow. In the last decades astronomers postulated a large range of models to explain the formation of these objects and the correlation of their masses with the host galaxy. Some of the theoretical explanations include very large seed masses, hyper Eddington or supra-exponential accretion, very massive metal-free super clusters, the collapse of the first baryonic structures and finally the formation of SMBHs via BH mergers. In this project we examine the formation of a supermassive object through the fusion of black holes in a black hole cluster embedded in gas, thus considering the effect of an external gas potential and post-Newtonian corrections. We study this model via N-body simulations using the Nbody6++ code. Here we present the results of 100 simulations, where we vary the mass of gas potential. As the simulations are extremely expensive when considering the real speed of light, we treat it here as a free parameter and determine results assuming different speeds of light, with the aim to extrapolate our results to the physical value. In this presentation we will provide preliminary results showing that a massive object can form via black hole mergers in the presence of on a analytic potential.
#095 |
Selection of LSST AGN Candidates using Photo-z
Sarath Satheesh Sheeba
1
;
Timo Anguita
1
;
Roberto Assef
2
1 - Universidad Andres Bello.
2 - Universidad Diego Portales.
Resumen:
LSST will be transformative regarding our understanding and knowledge about the nature and evolution of Active Galactic Nuclei (AGN). This will provide a unique view of the time-variable behaviour of AGN, allowing the identification of new variability classes while also discovering billions of new AGNs. These large datasets will enable new and larger statistical studies of these objects. Selecting these objects from purely photometric datasets is an active research problem. In this talk, I plan to allocate half of the time for presenting the results of our work in selecting AGNs from simulated LSST data through photometric redshift estimations. Our algorithm combines the simulated data provided by the LSST AGN Science Collaboration Data challenge (Yu et al., 2022) with the Low-Resolution spectral energy distribution Templates (LRT: Assef et al. 2010) to estimate photometric redshifts for all detected sources. By fitting and weighting multiple spectral templates (galaxy, galaxy+AGN, star) we obtain a relative likelihood of the possible nature, and thus a selection, of the sources. I will discuss the efficiency and speed of our algorithm, as well as its accuracy and validation through statistical tests. Furthermore, I will demonstrate how the use of multiwavelength photometric data such as WISE and UKIDSS could improve the purity and completeness of the sample and also about the current results on using variability timescales as a probe for redshift estimation.
#121 |
The Incidence of Mergers in Type I and II AGN from the MaNGA Sample
hector Hernandez Toledo
1
;
Edgar Cortes Suarez
1
;
Jose A. Vazquez Mata
1
;
Rebecca Nevin
2
;
Hector Ibarra Medel
1
;
Alenka Negrete
1
1 - Instituto de Astronomia, UNAM.
2 - Fermi National Laboratory.
Resumen:
We present a study on the incidence of major mergers and their impact on the triggering of nuclear activity in 47 type I and 236 type II optically selected AGN from the MaNGA DR15 sample. From an estimate of non-parametric image predictors (Gini, M20, concentration (C), asymmetry (A), clumpiness (S), S\'ersic index (n), and shape asymmetry (AS)) using the SDSS images, in combination with a Linear Discriminant Analysis Method, we identified major mergers and merger stages. We reinforced our results by looking for bright tidal features in our post-processed SDSS and DESI legacy images. We find a statistically significant higher incidence of major mergers of 29 per cent $\pm$ 3 per cent in our type I+II AGN sample compared to 22 per cent $\pm$ 0.8 per cent for a non-AGN sample matched in redshift, stellar mass, colour, and morphological type, finding also a prevalence of post-coalescence (51 per cent $\pm$ 5 per cent) over pre-coalescence (23 per cent $\pm$ 6 per cent) merger stages. The levels of AGN activity among our massive major mergers are similar to those reported in other works using [O III] tracers. However, similar levels are produced by our AGN-galaxies hosting stellar bars, suggesting that major mergers are important promoters of nuclear activity but are not the main nor the only mechanism behind the AGN triggering. The tidal strength parameter Q was considered at various scales looking for environmental differences that could affect our results on the merger incidence, finding non-significant differences. Finally, the H-$H\beta$ diagram could be used as an empirical predictor for the flux coming from an AGN source, useful to correct photometric quantities in large AGN samples emerging from surveys.
#141 |
NIR--IFU observations of the Seyfert~2 galaxy NGC~262
Juliana Cristina Motter
1
;
Rogério Riffel
1
;
Tiago Vecchi Ricci
2
;
Rogemar Riffel
3
;
Thaisa Storchi-Bergmann
1
;
Miriani Pastoriza
1
;
Alberto Rodriguez-Ardila
4
;
Daniel Ruschel-Dutra
5
;
Luis Gabriel Dahmer-Hahn
6
;
Natacha Zanon Dametto
7
1 - Universidade Federal do Rio Grande do Sul.
2 - Universidade Federal da Fronteira Sul.
3 - Universidade Federal de Santa Maria.
4 - Laboratório Nacional de Astrofísica.
5 - Universidade Federal de Santa Catarina.
6 - Shanghai Astronomical Observatory.
7 - Instituto de Astrofísica de Canarias.
Resumen:
NGC~262 is a local Seyfert~2 galaxy that hosts a hidden Seyfert~1 nucleus. In this work, we use adaptive optics (AO) assisted, near-infrared (NIR), integral-field unit (IFU) observations of NGC~262 obtained with the Gemini telescope in the \textit{J}-band to map the distribution and kinematics of the ionized gas in its inner $\mathrm{0.9\,kpc \times 0.9\,kpc}$ with a spatial resolution of $\approx \mathrm{55\,pc}$. Recently, Riffel et al. (2023) used AO assisted NIR--IFU \textit{K}-band observations of NGC~262 and found that this galaxy presents kinematically disturbed regions seen in ionized gas, which they interpreted as being due to nuclear outflows driven by the active galactic nuclei (AGN). Therefore, we will complement these results. In addition, our observations will allow us to map the distribution and kinematics of bluewings associated with the $\mathrm{[FeII]\lambda 1.257 \mu m}$ and $\mathrm{Pa\beta}$ emission lines that were identified by previous works based on integrated measurements and that could not be further characterized due to the lack of spatial resolution.
#146 |
Estudio del Disco de Acreción en AGN a través de Mapeos de Reverberación
Diego Gonzalez Buitrago
1
;
Teresa Garcia Diaz
1
1 - UNAM-Mexico, Ensenada.
Resumen:
We will present the results of an intensive observational study of Reverberation Mapping conducted on a group of Active Galactic Nuclei (AGN). To achieve this, we carried out intense multi-wavelength observation campaigns, ranging from X-rays to infrared (IR). Studies of Reverberation Mapping in multiple AGN have experienced a remarkable increase, providing results that are helping to resolve the paradigms governing these systems. The main findings are as follows: a) Temporal delays were obtained for different wavelengths, from X-rays to infrared, following the $\tau \propto \lambda^{4/3}$ relationship, as expected from the standard AGN accretion disk theory. b) Estimates of the size of the accretion disk suggest they are approximately 2-5 or even 11 times larger than predicted by the standard AGN accretion disk theory. However, solutions to this problem involving underestimated black hole masses have been proposed. c) The delays found for the light curves in the $U/u/r$ bands (3467\AA, 3540\AA, 6215\AA) deviate from the trend shown by the delays of the other bands that follow $\tau \propto \lambda^{4/3}$. This is likely caused by contamination from diffuse continuum emission of the Broad Line Region (BLR) or perhaps due to other inadequately considered components. d) The correlation of variability between the X-ray and UV light curves is weaker than the correlation between the UV and optical light curves, raising doubts about whether X-ray emission is the driver of variability at longer wavelengths.
#149 |
Investigating the potential of methanol as a shock tracer in the AGN-starburst galaxy NGC 1068 with UCLCHEM
Eva Méndez Robayo
1
;
Ko-Yun Huang
2
;
Serena Viti
2
;
Mario Higuera Garzón
1
1 - Observatorio Astronómico Nacional, Universidad Nacional de Colombia.
2 - Leiden Observatory, Leiden University.
Resumen:
The behavior of methanol ($CH_{3}OH$) in the composite galaxy NGC 1068 was analyzed to investigate its effectiveness as an extragalactic shock tracer and to study the effect of shock velocity ($v_{s}$) and formation routes (radical H-abstraction, hydrogenation, and pure gas-phase mechanisms) on the predicted interstellar abundance of methanol. With a parameterized C-shock physical model, C-shock chemistry was investigated with \texttt{UCLCHEM} to study the chemical abundance of $CH_{3}OH$ as a function of time in different locations of the Circumnuclear Disc (CND) near the active galactic nuclei (AGN) and the starburst ring of NGC 1068. It is concluded that the gas-phase methanol can trace C-type shocks as its abundance increases significantly due to grain sputtering or sublimation during shock propagation. This increase in the abundance of gas-phase methanol is consistent for both low ($\sim$ 10 km/s) and high ($\sim$ 45 km/s) velocity shocks. It is also shown that the main reaction leading to the formation of methanol in the grain is the H-abstraction mechanism, which is in good agreement with Simons et al. [2020] and Santos et al. [2022]. These modeling results will be contrasted with observed methanol abundance from Atacama Large Millimeter/submillimeter Array (ALMA) (Huang et al in prep; Vroom et al. in prep.) and discussed with different parameters explored, such as gas temperature ($T_{k}$), density ($n_{H_{2}}$), and cosmic-ray ionization rate ($\zeta_{0}$) and their dependence on methanol formation under the studied conditions.
#178 |
The universal optical power spectrum of Active Galactic Nuclei
Patricia Arevalo
1
;
Paulina Lira
2
;
Paula Sánchez-Sáez
3
;
Priyanjali Patel
2
;
Lorena Hernández García
1
;
Elena López Navas
1
;
Santiago Bernal
1
;
Eugene Churazov
4
1 - Universidad de Valparaíso.
2 - Universidad de Chile.
3 - ESO.
4 - MPA.
Resumen:
Quasars optical variability gives us clues to understand the accretion disc around supermassive black holes, which are responsible for the emission in this band and also for at least part of its variability. We can expect variability properties to correlate with the main physical properties of the accreting black hole, i.e. its mass and accretion rate. Specifically, we aim at establishing the dependence of variability properties, such as characteristic timescales $t_b$ and amplitude of the variability on black hole mass and accretion rate, controlling for the restframe wavelength of emission. We selected the g-band light curves for 4770 objects from the Zwicky Transient Facility archive that fall into a narrow redshift bin, but cover a wide range of accretion rates in Eddington units (REdd) and black hole masses (M). With these, we found a clear dependence of $t_b$ on REdd, on top of the known dependence of $t_b$ on M. In our fits, $t_b\propto M^{0.65 - 0.55} REdd^{0.35 - 0.3}$ scaling $t_b$ to the orbital timescale of the ISCO, $t_{ISCO}$, results approximately in $t_b/t_{ISCO} \propto (REdd/M)^{0.35}$. In the standard thin disk model, $(REdd/M)\propto T_{max}^4$, where $T_{max}$ is the maximum disk temperature, so that $t_b/t_{ISCO}$ appears to scale approximately with the maximum temperature of the disc. The observed values of $t_b$ are about 10 times the orbital timescale at the light-weighted average radius of the disc region emitting in the (observer frame) g-band. The different scaling of the break frequency with M and REdd shows that the shape of the variability power spectrum cannot be solely a function of the quasar luminosity, even for a single rest-frame wavelength.
#194 |
The DIVING$^\mathrm{3D}$ project: a deep look on the central region of early-type galaxies
Tiago Vecchi Ricci
1
;
Roberto Bertoldo Menezes
2
;
Katia Slodkowski Clerici
3
;
Maico Douglas da Silva
4
;
Patricia da Silva
5
1 - Universidade Federal da Fronteira Sul.
2 - Instituto Mauá de Tecnologia.
3 - Universidade Federal do Rio Grande do Sul.
4 - Universidade Federal de Santa Maria.
5 - Instituto de Astrofísica, Geofísica e Ciências Atmosféricas da USP.
Resumen:
Most galaxies with well-defined bulges host a supermassive black hole (SMBH) in their centre. An active galactic nucleus (AGN) arises when a considerable quantity of matter is accreted onto SMBHs. In elliptical and lenticular galaxies from the local Universe, low-luminosity AGNs (LLAGNs), usually with LINER-like spectra, are predominant. In this work, I will present the final results on the nuclear region of all 56 early-type galaxies (ETGs) from the DIVING$^\mathrm{3D}$ project, which is a statistically complete sample containing all galaxies from the Southern hemisphere brighter than 12.0 mag (B-band) and galactic latitude $|b| < $ 15$^\mathrm{o}$. All observations were performed with the GMOS-IFU instrument installed at the Gemini South telescope. We detected emission lines in 86$\pm$5\% of the objects. In 52$\pm$7\%, the emission was classified as characteristic of LINERs or Seyferts. No emission of the H$\beta$ or the [O {\sc iii}]$\lambda$5007 lines was detected in the other 34$\pm$6\% of the ETGs. Given their low values of the equivalent width of H$\alpha$, we classified them as weak emission line objects. No Transition Objects (composite H {\sc ii}/LINER spectra) were detected in the sample. Broad components are seen in the H$\alpha$ line of 29$\pm$6\% of the nuclei. In 41 out of 48 galaxies with ionized nebulae, the source of ionization for the LINER spectra and for some of the weak emission line objects is likely due to a LLAGN, although some of the objects require shocks to explain high values of the [O {\sc i}]$\lambda$6300/H$\alpha$ ratio. Lenticular galaxies are more likely to have emission lines than ellipticals. We also found that more luminous galaxies tend to have higher [N {\sc ii}]$\lambda$6584/H$\alpha$ ratios. Two possible reasons for this result are the mass-luminosity relation of galaxies or differences in the excitation conditions of the gas.
#202 |
UV spectral characterization of quasar
Tania M. Buendia-Rios
1
;
Paola Marziani
2
;
C. Alenka Negrete
1
;
Nancy Jenaro
1
1 - Instituto de Astronomía, UNAM.
2 - INAF, Osservatorio astronomico di Padova.
Resumen:
Quasars accreting at high rates are considered key drivers of galactic evolution due to their significant radiative and mechanical feedback. In this work, we analyzed LUCI-LBT observations from a sample of highly accreting quasars at z$\sim$2 in the H$\beta$ spectral range, redshifted to the NIR, to achieve a precise determination of the quasar systemic redshift and accretion parameters (black hole mass and Eddington ratio). Additionally, we examined the corresponding spectra in the UV range from the SDSS, where the CIV$\lambda$1549 emission line profile serves as a tracer of the high-ionization nuclear winds.
These data allowed us to estimate the outflow mechanical output (including mass flow, kinetic power, and thrust). We were also able to assess the dynamical properties of the wind originating from the accretion disk and study its connection with the accretion parameters while exploring the possibility of chemical feedback.
#213 |
Use of Neon lines in the study of the components present in SEDs of Seyfert Galaxies
Jonhatan H. Bernal Salinas
1
;
Andrés F. Ramos Padilla
2
;
Mario-A Higuera-G
1
1 - Universidad Nacional de Colombia, Observatorio Astronómico Nacional.
2 - Groningen University; SRON Netherlands Institute for Space Research.
Resumen:
The emission line of [Ne V], in infrared, has proven to be a relevant indicator of the activity of an AGN due to its high ionization potential. Likewise, the analysis of the ratio [Ne V]/[Ne II], has allowed to distinguish between stellar environments and AGNs. Based on the above, this work sought to verify from a sample of Seyfert galaxies taken from the CDS-SIMBAD database, that the estimates of the AGN fraction ($f_{AGN}$) coming from a spectral energy distribution (SED) modeling tool (CIGALE), coincide with the Neon line tracers in the infrared. From NED tables, galaxies containing data on the lines [Ne II]12.8$\mu$m, [Ne V]14.3$\mu$m, and [Ne III]15.5$\mu$m were filtered from the initial sample. [Ne V]/[Ne II], [Ne V]/[Ne III], and [Ne III]/[Ne II] ratios were compared with the different physical properties estimated from the best SED model of each galaxy. It was found that the correlation between $f_{AGN}$ and the [Ne V]/[Ne II] ratio is strong in galaxies classified as Seyfert 1 in the initial sample, but weak in those classified as Seyfert 2. This same pattern occurs by classifying galaxies by their viewing angle ($i$) to the torus and classifying by the luminosity of the AGN disk ($L_{AGN}^{disc}$).
#215 |
Using WISE cataloged data for morphology, bulge fraction and black hole mass estimation
Joaquín Hernández-Yévenes
1
;
Neil Nagar
1
;
Vicente Arratia
1
;
Thomas H. Jarrett
2
1 - Universidad de Concepción.
2 - University of Cape Town.
Resumen:
We present WISE2MBH, an efficient algorithm for estimating key parameters of supermassive black holes (SMBH) in galaxies. By leveraging photometric data from the Wide-field Infrared Survey Explorer (WISE) and employing scaling relations, WISE2MBH estimates the morphological type, bulge fraction, bulge mass, and SMBH mass ($M_\text{BH}$). The algorithm distinguishes between QSO and regular galaxies, determining the morphological type and bulge fraction using WISE information calibrated against morphological classifications from the 2MASS Redshift Survey (2MRS). With k-corrections applied, WISE2MBH performs well up to $z\sim0.5$, providing reliable $M_\text{BH}$ estimates. When compared to a sample of local galaxies with measurements and high-precision estimates of $M_\text{BH}$, our algorithm shows optimistic results, with a Spearman score of $\sim0.8$, R-squared of $\sim0.68$, and root mean square error (RMSE) of $\sim0.52$. Applying WISE2MBH to the ETHER sample yields approximately 2.4 million $M_\text{BH}$ estimates and 650 thousand $M_\text{BH}$ upper limits, with $\sim80\%$ of sources lacking previous $M_\text{BH}$ estimates. Our algorithm will be a valuable tool for target selection for the Event Horizon Telescope (EHT) and the next-generation EHT (ngEHT). The WISE2MBH algorithm is publicly available on GitHub.
#251 |
Accretion disk study of the AGN ESO 362-G18 through reverberation mapping
Pablo Sebastian Vazquez Loreto
1
;
Diego Hernando González Buitrago
2
1 - Universidad de Sonora.
2 - IA-UNAM.
Resumen:
ESO 362-G18 is a Seyfert 1.5 nearby galaxy, with z~0.0012. Whose nucleus carries Active Galactic Nuclei, which contain a supermassive black hole with a mass of about $4.5\times10^7$ solar masses (Bennert et al., 2006). This galaxy displays remarkable features, like a high bolometric luminosity of up till $L_{bol}\sim 1.3\times10^44$ erg/s, which implies an accretion rate near 0.02 of Eddington rate.
In addition, ESO 362-G18 has demonstrated a large time variability, from hours to years, at all wavelengths, from X-Ray to IR. In this study, we present a temporal variability analysis of this AGN in various frequency bands obtained through a Swift Space Telescope observational survey.
We have done reverberation mapping studies to estimate the geometry and size of the accretion disk in ESO 362-G18, following the theoretical model of Shakura and Sunyaev (1973), which explains an optically thick and a geometrically thin accretion disk. For this analysis, we have used advanced techniques, including specialized codes such as JAVELIN and PYCCF, which allow us to quantify the relationship between the temporal variability of the object and the lag times concerning a reference light curve. In this case, we have chosen the UV band (2248$\AA$) as a reference since it comes from the inner region of the accretion disk, providing relevant information about its dynamic behavior.
Our results provide a deeper understanding of the physical and dynamic properties of ESO 362-G18, as well as the processes in its active cores. This work contributes to advances in AGN astrophysics and our understanding of supermassive black holes and their interactions with the galactic environment.
#259 |
Star Formation Histories on the COSMOS-Web galaxies: Preliminary.
Rafael Arango
1
1 - Laboratorio de Astrofísica de Marsella.
Resumen:
With the arrival of the first data of the James Webb Space Telescope (JWST), the scientific community has had access to amazing samples to study galaxy evolution. The past decade has seen tremendous progress in the Spectral Energy Density (SED) fitting techniques, allowing us to extract physical parameters from a wide wavelength baseline, such as the Star Formation and its evolution with time, which play a fundamental role to characterize the evolving galaxies. This work is based on the Code Investigating Galaxy Emission (CIGALE), assuming a large variety of non-parametric star formation histories (SFHs). In this presentation I will first show a short example on the study of radio emission as star formation tracer, focusing on the timescale probes by the radio in the light of the reconstructed SFH. Then I will present results on the creation of physical parameters catalogs from the most recent COSMOS-web observations. I will discuss the robustness of CIGALEs' non-parametric SFHs using The Horizon-AGN Hydrodynamic simulation to finally present preliminary results on the galaxy main sequence from the COSMOS-web survey.
#315 |
Spatially resolved observations of the peculiar galaxy NGC\,232: AGN winds and stellar populations
José Henrique Costa Pinto Souza
1
;
Rogemar André Riffel
1
1 - Universidade Federal de Santa Maria.
Resumen:
We use the optical integral field spectroscopy, obtained with the VLT-MUSE instrument, to study the stellar populations and gas properties and kinematics of the Seyfert 2 galaxy NGC\,232. The data cover a field of view of 60\,$\times$\,60\,$arcsec^{2}$ at a spatial resolution of $\sim$850\,pc. We fit the emission-line profiles with two Gaussian components, one associated to the emission of the gas in the disk and the other due to a biconical outflow. The previously reported jet-like optical structure in this galaxy seems to be associated to the emission of the closer wall of bicone. We have found that the stellar population is predominantly Old t\,>\,2Gyr.
The AGN seems to quench the star formation in the inner 2\,kpc. On the other hand, a higher contribution of younger stellar populations is seen surrounding the walls of the bicone, suggesting a both negative and positive feedback scenario. Regarding the chemical abundance, AGN-dominated and SF-dominated regions show similar abundances of oxygen.
#348 |
Test for obtaining black hole masses using photometry in high redshift quasars
Yanina López
1
1 - Universidad de Valparaíso.
Resumen:
Quasars are extremely energetic and luminous active galactic nuclei, allowing their radiation emitted from the earliest times of the Universe to be detected. This work studied the obtaining of black hole masses from 24 quasars in a redshift range of 5.8 < z < 6.5 belonging to the XQR-30 sample (The ultimate XSHOOTER quasar sample at the reionization epoch) part of the ESO Large Programs. For this was used a code developed by Samuel Lai for accretion disk fitting with Slim and Thin models, as well as MCMC Bayesian interference to limit the inherent degeneracies of the problem. This code uses only photometric data, so in principle, it can be a powerful tool for obtaining masses of large numbers of quasars without needing expensive spectra. The spectroscopic sample is used as a comparison between traditional methods of obtaining masses with the results obtained in this study. The scatter of the realizations values is tested and the relevance of this method and its possible improvements are discussed.
#380 |
Ionized gas winds from the nucleus of OH megamaser galaxy IRAS 09320+6134
Claudia Marzari Cassanta
1
;
Rogemar Riffel
1
1 - Universidade Federal de Santa Maria.
Resumen:
[Ultra]luminous infrared galaxies are extremely bright objects in this spectrum range, with luminosities bigger than 10$^{11}$\,L$_{\odot}$. These objects, which typically consist of mergers and interactions of galaxies, are propitious environments for the emission of OH megamasers, luminous and powerful extragalactic masers. Many host systems of this phenomenon seem to present a composite spectrum, both with characteristics associated with Starbursts and with the presence of an AGN. IRAS 09320+6134 is part of a project whose general objective is to relate the properties of the megamaser emission and the merger stage of its host galaxy with possible AGN and/or Starburst activities, in order to better understand the nature of the ionization mechanism of galaxies that present this phenomenon. The observations were performed on Gemini North telescope, using GMOS spectrograph in IFU mode. IRAS 09320+6134 has an estimated infrared luminosity of L$_{IR}=10^{11.95-12.02}$\,L$_{\odot}$. The adjustment of the profiles of the emission lines present in the spectra was done with two Gaussian curves. The flux distributions show extended emission in all lines for both components, with the emission of the narrow component being observed in the whole field of view and the emission of the broad component seen mainly in the central $1.5''$. The narrow component is tracing gas emission in the galaxy's disk, and the velocity fields of this component show a rotating disk. The broad component presents only negative velocities and is interpreted as being due to an outflow of ionized gas from the galaxy's nucleus. BPT and WHAN diagnostic diagrams for both components indicate that the ionization is predominantly due to the presence of an AGN. Preliminary estimates of the outflow properties indicate that its kinetic power is around 2 orders of magnitude less than the values estimated by cosmological simulations for the AGN feedback to be efficient in suppressing star formation.
#450 |
PAH astrochemistry — spying on the underlying power source in dust-rich galaxies
Yanna Martins-Franco
1
;
Karin Menendez-Delmestre
1
;
Thiago Signorini Goncalves
1
1 - Observatorio do Valongo (UFRJ).
Resumen:
One of the most challenging aspects of studying the interstellar medium (ISM) of active galaxies is the intense obscuration by dust. This phenomenon raises a series of debates about the most notable power engine of active galaxies: star formation activity, nuclear activity (AGN), or a combination of both. One way to investigate this issue is by inspecting the dust, particularly the Polycyclic Aromatic Hydrocarbons (PAHs). This class of complex molecules, detected by their broad features at mid-infrared, is a tracer of ionizing radiation by young stars, ubiquitous in the universe, and, more recently, has been found even in circumnuclear regions of AGN. In this work, we use low-resolution spectroscopy by IRS/Spitzer to probe the ISM astrochemistry in 600 dust-rich galaxies to explore the relationship between PAH molecular diversity (size, charge, and composition) and the AGN strength. We use a sample of dusty galaxies (0$\textless$z$\textless$3.7) encompassing different nuclear activity degrees, such as pure starbursts, U/LIRGs, Seyfert galaxies, and quasars. We proceed with a spectral decomposition and a molecular breakdown, using a suite of theoretical spectra from PAH vibrational transitions. We notice PAH infrared emission is well represented by neutral, small ($\textless$50 atoms of Carbon), and pure molecules (with no metal, except Carbon). We see stronger AGNs seem to host more neutral PAHs (77\%$\pm$15\%) than star-forming galaxies (56\%$\pm$10\%), which can be explained by shielding of molecular gas and photochemical processes, such as electronic recombination and PAH dehydrogenation, where the latter may be favored in stronger AGN. These results help us to understand how the dust is affected by the coexisting activities of supermassive black hole growth and star formation bursts that occur in the evolution process of gas-rich galaxies. With the new generation of IFU instruments, the technique developed in this work can be used to explore the ISM of dusty galaxies.
#451 |
Morphological study of active galaxies
Julián Esteban Becerra Bernal
1
;
Nelson Vera Villamizar
1
1 - Universidad Pedagógica y Tecnológica de Colombia.
Resumen:
Spiral galaxies are a type of galaxy commonly found in observations of the nearby universe and 20th century observational studies have identified the presence of active nuclei (AGN) in some of them. In this study, we search for pairs of galaxies with the same morphological type, where one has an AGN and the other does not, in order to look for structural differences that point, at the global galaxy level, to the factors that generate nuclear activity in the galaxy. The image search for this work was performed using databases such as The Sloan Digital Sky Survey III (SDSS-III). From our selection, we checked most of the basic physical data (size, etc.) in NASA/IPAC Extragalactic Database. In addition, to correlate nuclear activity with galactic morphology, we used the fourier method and identified the corrotation resonance.
#460 |
The environment of LBAs in the S-PLUS
Vitor Hugo Lopes da Silva
1
;
Thiago Signorini Gonçalves
1
;
Arianna Cortesi
1
1 - Observatório do Valongo - UFRJ.
Resumen:
High redshift galaxies form about 10 times more stars per unit time compared to galaxies in our local universe, but we do not know whether the trigger for this high star formation rate is related to interactions with the environment of these galaxies or to star formation in internal clumps due to instabilities. The main objective of this project is to investigate the environment of analogues of high-redshift star-forming galaxies, with the objective of determining a possible correlation between the local density and the physical properties related to the star formation process. These results will later be compared with galaxies in the distant universe, in order to allow for an evaluation of the influence of the local environment on the formation of galaxies 10 billion years ago. Our methodology consists of the k-th nearest neighbor method with k = 4, 5 and 10, then comparing the density values with different k. For this, we used data from the S-PLUS survey, which will observe ~9300 deg² of the celestial sphere in the southern hemisphere, in 5 wide bands and 7 narrow bands. The use of narrow bands, in particular, allows for a much more precise measurement of photometric redshifts, significantly improving density measurements. To find the analogues, we combined the S-PLUS data with the GALEX data. Preliminary results indicate that analogues are found in low-density environments on a large scale, while on a smaller scale they are in denser environments, indicating that interactions with the environment, such as mergers, may be responsible for the high rate of star formation.
#481 |
A comparative of two dual AGNs mergers
Márlon Carvalho de Castro
1
;
Daniel Ruschel Dutra
1
;
Giovana Conod
1
1 - Universidade Federal de Santa Catarina (UFSC).
Resumen:
The evolution of galaxies and its connection with Active Galactic Nuclei (AGNs) feedback on either suppressing or enhancing star formation remains a subject of ongoing discussion. While there is a theoretical understanding that AGN outbursts can provide enough energy to heat the gas and consequently suppress star formation, the extent to which this thermal energy effectively serves this purpose remains uncertain.
This research investigates the link between the evolution of Super Massive Black Holes (SMBHs) and their host galaxies through merger galaxies. From integral field spectrographs (IFS) observations, we compare two merging galaxies: SDSS J1414-0000 ($z$=0.0475) in the early stages of collision; and SDSS J1544-0441 ($z$=0.042) in a more advanced stage, with projected nuclear separations of $\sim$ 4.9 kpc and $\sim$ 3.4 kpc respectively. The two objects have AGN signs on both nuclei, based on the data from the Chandra X-ray Survey. Although we're working with pre-processed MUSE datacubes retrieved from ESO, it's worth noting that we might undertake further data reduction to address issues such as missing sky subtraction factors and flat influences.
In order to derive the stellar continuum, we employ STARLIGHT. This software applies a linear combination of stellar population models and comes up with the best fit while accounting for factors such as the kinematic broadening of the absorption lines and reddening. In addition, we fit the emission line profile of ionized gas using IFSCUBE, which also provides some kinematic properties such as radial velocity and velocity dispersion. This approach enables us to analyze the effects of the merger process on gas flow toward and outward of the core.
As initial findings, we compare the [OIII]$\lambda$5007/H$\beta$ ratio with the [NII]$\lambda$6583/H$\alpha$ ratio (BPT diagram) for every spaxel of SDSS J1414-0000 nuclear region, confirming one nuclei as HII/AGN composite and another as an AGN, consistent with prior observations.
#544 |
Chemical abundances of LINER galaxies - Nitrogen abundance estimations
Celso B. Oliveira Junior
1
;
Ângela C. Krabbe
2
;
Oli L. Dors Junior
1
;
Igor A. Zinchenko
3
;
Jose A. Hernandez-Jimenez
1
;
Monica V. Cardaci
4
;
Guillermo F. Hägele
4
1 - IPD/Univap.
2 - IAG/USP.
3 - LMU Munich.
4 - Instituto de Astrofísica de La Plata.
Resumen:
In this work, we investigated the nitrogen and oxygen abundances in a sample of galaxies with Low Ionization Nuclear Emission Regions (LINERs) in their nucleus. Optical spectroscopic data (3600 - 10000 \AA) of 40 LINERs from the Mapping Nearby Galaxies (MaNGA) survey were considered. Only objects classified as
retired galaxies, i.e. whose main ionization sources are post-Asymptotic Giant Branch (pAGB) stars, were selected. The abundance estimates were obtained through detailed photoionization models built with the cloudy code to reproduce a set of observational emission line intensities ratios of the sample. Our results show that LINERs have oxygen and nitrogen abundances in the ranges of 8.0 < 12+ log(O/H) < 9.0 (mean value $8.74\pm 0.27$) and 7.6 < 12+ log(N/H) < 8.5 (mean value $8.05 \pm 0.25$), respectively. About 70\% of the sample have oversolar O/H and N/H abundances. Our abundance estimates are in consonance with those for Seyfert 2 nuclei and HII regions with the highest metallicity, indicating that these distinct object classes show similar enrichment of the interstellar medium (ISM). We found a correlation between the nitrogen and oxygen abundances inferring that the ISM nitrogen enrichment in LINERs seems to mainly have a secondary production. Our results show that LINERs do not present any correlation between the N/O abundances and the stellar masses of the hosting galaxies.
#596 |
Abundances of PBHs from Optical and X-ray Quasar Microlensing Observations: Constraints to the DM Fraction
Ana Esteban-Gutierrez
1
;
E. Mediavilla
2
;
J. Jiménez-Vicente
3
;
J.A. Muñoz
4
;
N. Agües- Patzkowsky
2
;
S. Heydenreich
5
1 - Universidad de Valparaiso.
2 - Instituto de Astrofísica de Canarias, Universidad de La Laguna.
3 - Departamento de Física Teórica y del Cosmos ; Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada.
4 - Departamento de Astronomía y Astrofísica, Observatorio Astronómico, Universidad de Valencia.
5 - Argelander-Institut fur Astronomie.
Resumen:
Quasar microlensing is a very powerful tool that allows us to estimate the mass and the abundance of any kind of compact object in the lens galaxies. According to the mass range considered for the microlenses and the size of the source, we are capable of accounting for the effect of the microlenses to each macro image of the source and obtain the corresponding magnification maps. Recent results coming from GW experiments (LIGO/Virgo) raised again the interest in studying other candidates of BHs to be part of the elusive DM nature. I present the results of applying this technique using optical (Esteban-Gutierrez et al. 2022a, 2022b) and X-ray (Esteban-Gutierrez et al. 2023) observations and a Bayesian analysis to constraint the abundance of a possible population of PBHs mixed within the stars, which could explain the observed amount of DM in these lens galaxies. The mass range explored from planetary to intermediate-mass PBHs ($\sim10^-3$Msun - 60Msun) sets the most complete coverage of this area according to microlensing studies and provides results for the estimated fraction of the DM (Esteban-Gutierrez et al. 2023).
Poster Group II (Wed - Fri) - J: Cosmology
#026 |
Did black hole-jets induced the formation of the first PoP-III stars?
Felix Mirabel
1
1 - IAFE-UBA.
Resumen:
The existence of supermassive black holes (SMBHs) of $10^9$ solar masses in quasars when the age of the universe was less than 700 Myr is an intriguing puzzle. How the seeds of these SMBHs have been formed and have grown so fast to become so large?
I will briefly review recent models in the context of dark matter cosmologies where the seeds of the SMBHs at redshifts $z > 6$ are formed by direct collapse of dark matter haloes, before the formation of Pop III stars. Then I will review recent observations that suggest MBHs in primordial galaxies come first and grow faster than stellar populations. In this context, and based on observations in the local and distant Universe, I will conclude that jets from the rapidly growing seeds of the SMBHs in the early universe would have induced the formation of the first massive stars of Pop III.
#072 |
Forecasting cosmological constraints from the velocity angular power spectrum of type Ia supernovae
João Pedro Bonifacio
1
;
Thiago Gonçalves
1
;
Bruno Moraes
2
1 - Observatório do Valongo - UFRJ.
2 - Instituto de Física - UFRJ.
Resumen:
Type Ia Supernovae (SNIa) are fundamental distance indicators for cosmology thanks to their nature as standardizable candles. In the next few years, the Rubin Observatory Legacy Survey of Space and Time (Rubin LSST) will provide a sample of millions of SNIa due to its large sky coverage and high cadence. Apart from the direct measurement of cosmological parameters with traditional methods of SNIa analysis, this sample can be used to measure the growth rate of structures in the universe through the study of peculiar velocities. These velocities are caused by the gravitational attraction of the large-scale structure of the universe: as galaxies (and their SN) tend to move towards denser regions, objects in the same region of the sky have correlated velocities. These correlations can be employed to study the intensity of the gravitational interaction on large scales. Current techniques rely on traditional three-dimensional statistical estimators for the data analysis. However, these estimators are inconvenient for application to Rubin LSST data, which will use angular power spectra to extract cosmological signals from galaxy overdensities and gravitational lensing. In this study, we will apply the Fisher information matrix methodology to the angular power spectrum of SNIa peculiar velocities. The main goal is to demonstrate the viability of using this estimator for the expected Rubin LSST data, comparing its constraints with those of traditional 3d estimators. We will investigate scenarios with velocities alone, and in combination with galaxy density and gravitational lensing observables (so-called "3x2pt" observables). We will explore the impact of different assumptions on the observational properties of the sample. This is a first step towards future measurements of cosmological parameters using a combination of Type Ia supernova peculiar velocities and 3x2pt cosmological estimators in the context of Rubin LSST.
#193 |
ANALYSIS OF THE EXPANSION OF THE UNIVERSE USING LARGE-SCALE STRUCTURES
Mariana L.S.Dias
1
;
Armando Bernui
1
;
Felipe Avila
1
1 - Observatório Nacional.
Resumen:
The Hubble-Lemaître Law provides a satisfactory description of the universe's dynamics for low redshifts and reveals insights about its expansion rate. However, at higher redshift values, additional incorporation of the Friedmann equations within the framework of General Relativity is necessary. This project focuses on analyzing large-scale structures of the local universe, specifically at low redshifts, using Hubble-Lemaître diagrams. The goal is to understand the dynamics of universe expansion by studying the Hubble constant independently of specific cosmological models. By utilizing the ALFALFA catalog, the Hubble constant is measured, considering potential systematic effects and using velocity reference frames that minimize peculiar velocity influences. Transformations of frames of reference, e.g. Local Group and CMB frames, and statistical methods were employed to achieve a more accurate determination of the Hubble constant. Within 1 sigma confidence level, the values for the Hubble constant are equivalent between the two hemispheres. The findings of this work, which contributed to the publication of an article, shed light on the precise measurement of the Hubble constant and its implications.
#379 |
Exploring the dynamical systems and observational constraints of cosmological models in mimetic gravity
Carlos Hugo López-Caraballo
1
;
Alberto Fritis Puga
2
;
Daniel Ignacio Villalobos Silva
2
;
Yerko Vásquez
2
1 - Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain.
2 - Departamento de Física, Universidad de La Serena, Avenida Cisternas 1200, La Serena, Chile..
Resumen:
In the last decades, the $\Lambda$-CDM model have been supported by observations of the Cosmic Microwave Background (CMB), type Ia supernovae (SN Ia), the Hubble parameter and Baryonic Acoustic Oscillations (BAO), and have yielded cosmological parameters with precisions of the order of one percent (e.g. the CMB analysis). Nevertheless, there are still theoretical and observational claims that departs of the $\Lambda$-CDM paradigm. This opens the door to explore alternatives such as the $f(R)$-modified gravity theory, string-inspired models with a Gauss-Bonnet dilaton coupling, Horndeski gravity and massive gravity. In this context, we consider the mimetic gravity which is an interesting modification of the gravitational theory that provides a geometric description of dark matter and dark energy. This gravity theory is a Weyl-symmetric extension of General Relativity, related to the latter by a singular disformal transformation with extra degrees of freedom and these can mimic cosmological components. In this poster, we will present the dynamic description of the isotropic and homogeneous Friedmann-Lematre-Robertson-Walker cosmological models with spatial curvature coming from mimetic gravity theory. The phase space obtained allow us access to solutions that can represent different stages of the cosmic evolution. We therefore can obtain properties of the cosmological models that can be compared with the Observational Hubble database from the cosmic chronometers (OHD) and the Pantheon database from type Ia supernovae (PaSNe). In this poster, we will also present a brief discussion on the observational properties of the $\Lambda$-CDM model and models for mimetic fields with exponential potential (EP) and with quadratic rotational potential (QRP), with emphasis on the cosmological constraints provided by this study.
#504 |
Modeling the chemistry in the early Universe
MARIA SEGOVIA
1
;
Dominik Schleicher
1
;
Stefano Bovino
1
;
Daniele Galli
2
1 - Universidad de Concepción.
2 - INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5.
Resumen:
The chemistry of the early universe consisted mainly of simple atomic species and molecules composed of hydrogen and helium. Therefore, to understand the chemistry of the early universe it is necessary to know the chemical processes that these species underwent. Also, the interaction with the Cosmic Microwave Background (CMB) is the best test for determine the evolution and abundance of the primordial chemistry.
To model the early chemistry, we will estimate the abundance of these species as a function of redshift using the chemistry package KROME.
We focus in the $HeH^+$ molecule, because this molecule has a high dipole moment and is formed by quite abundant species. Also, its contribution to the optical opacity affecting the CMB. For this molecule we will explore new rates, such as dissociative recombination and photodissociation, and their impact on abundance.
The importance of studying the formation and destruction processes of primordial molecules is that they allow us to estimate the abundance, which is important to understand the formation of the first stars in the universe.
#539 |
Unveiling Intermediate Redshift Galaxy Clusters in the Fornax Field with NGFS.
Juan Pablo Carvajal
1
1 - Pontificia Universidad Católica de Chile.
Resumen:
The Next Generation Fornax Survey (NGFS) has been instrumental in advancing our understanding of various astrophysical phenomena. This survey features very deep stacks of images from visible (DECam u, g, i) to infrared (VIRCAM J, Ks) wavelengths with unprecedented care for photometric calibration standards. Building on this rich tradition, we present the first results of the ongoing effort to study the clusters in this survey, going beyond the local universe. So far, our methodology for studying cluster is comprised in a four-step pipeline: meticulous photometric analysis, photometric redshift calculation using Bayesian Photometric Z (BPZ; Benitez, N. et al 2004), cluster detection using PZWav (Gonzalez, A. 2014), and estimation of galaxy membership probabilities. We are also in the process of including a step to estimate the physical properties of these clusters. As to be expected, our preliminary results in the first of seven tiles (>~3 sq. deg. per tile) reveal an array of structures including voids and filaments, visualized using Voronoi Tessellations. Due to the gaps in the spectral coverage, between the challenges we face there are photometric redshift degeneracies, and thus, redshift deserts. Despite this, for the first tile we detect 37 clusters with 5-$\sigma$ confidence (20 being at 1.4>z>0.9). These early findings are validated by the detections at low redshift matching the DESI Legacy Survey clusters in this field in more than half of the cases. Although the coverage of NGFS is much smaller than other surveys, it reaches higher redshift, potentially opening for empirical conclusions to be drawn in this window to the universe in the galaxy evolution front.
#604 |
The dark sector window with extreme laser pulses
Pablo Pais
1
;
Serguei Bulanov
2
1 - Instituto de Ciencias Físicas y Matemáticas, Universidad Austral de Chile, Chile - IPNP - Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic.
2 - ELI Beamlines Facility, The Extreme Light Infrastructure ERIC , Za Radnici 835, DolniBrezany 25241, Czech Republic - National Institutes for Quantum and Radiological Science and Technology (QST), Kansai Photon Science Institute, Kyoto, Japan.
Resumen:
Parameter bounds for the dark matter candidates can be obtained not only from astrophysical sources or large particle colliders but also from laser experiments. One of these experiments consists of shining a wall with a laser and trying to convert the photon into a dark matter candidate particle through an external magnetic field coupling, named light shining through the wall (LSW). On the other side of the wall, another magnetic field region would reconvert the weak interacting particle into a photon again before passing through a detector. We explore the possibility of implementing LSW to detect dark matter candidates, taking advantage of the power laser pulses achieved at the Extreme Light Infrastructure shortly.
#607 |
Post-Newtonian Dark Matter Galactic Halos
Ericson López
1
1 - Quito Astronomical Observatory.
Resumen:
In this contribution, we are interested in enforcing results reported in other works, where the main statement is that the general relativity formalism is not necessary to describe the physics of the halo around spiral galaxies. Then, an inter-median formalism between the classical Newtonian and the relativistic Tolman Oppenheimer Volkoff ones is used to model a halo filled with perfect fluid and equation of state obtained for the universal rotation curves of spiral galaxies. In order to keep the hydrostatic equilibrium the dark matter should have a nonzero pressure to compensate for the gravitational force of the mass contends in the halo. Then a state equation is demanded in order to accomplish this requirement and completes the set of space-time nonlinear gravitation field equations obtained from general relativity.
#235 |
Comparing the source GW170817 with light curves
of type Ia supernovae: They converge to the same value of
H0?
Rafael Girola Schneider
1
1 - Universidad Nacional de Tres de Febrero.
Resumen:
The work presented at this meeting is an extension of a work presented at a hole conference
Black Holes held in Foz de Iguaz´u,(International Conference on Black Holes as Cosmic Batteries: UHECRs and
Multimessenger Astronomy - BHCB2018 September 12-15, 2018 Foz do Igua¸cu, Brazil ) whose title was: “Type Ia
Supernovae and fusion of black holes: Do they complement each other in measuring the expansion of the universe?
Its objective is to answer, if it is possible to make measurements of cosmological distances, complementing
type Ia supernovae with the merger of black holes, evaluating if it is possible to refine the measurement of the expansion
acceleration of the Universe, through the detection of gravitational waves generated by the merging of holes
black by comparing them with the intrinsic luminosity of type Ia supernovae. The methodology is shown
used with the results obtained in the previous work, to contrast the simulation of results with the
obtained result. In this work the methodology of the previous work is extended, contrasting the results
virtual with those obtained in the publication of the work “A gravitational wave standard siren measurement of
the Hubble constant”, applying a novel approach to measure the Hubble constant by means of waves
gravitational forces, applying for the first time a revolutionary method proposed 30 years ago by Bernard Schutz
using source GW170817, detected by Advanced LIGO and Advanced Virgo on August 17, 2017. The
analysis of the gravitational waveform from the merger of black holes or neutron stars allows
to estimate the distance, which allows us to compare, according to the environment of the host galaxy, in relation to
to its environment, the comparison of light curves of supernovae, type Ia contrasting the results, in the distance
and what is the result of H0.
Poster Group II (Wed - Fri) - J: Early Universe
#137 |
Primordial Power Spectrum from an objective collapse mechanism: the simplest case
Martín Miguel Ocampo
1
;
Octavio Palermo
2
;
Gabriel León García
2
;
Gabriel Bengochea
3
1 - Instituto de Astrofísica de La Plata, CONICET-UNLP.
2 - Facultad de Ciencias Astronómicas y Geofísicas, UNLP.
3 - Instituto de Astronomía y Física del Espacio, CONICET-UBA.
Resumen:
In this presentation we will analyze the physical origin of the primordial inhomogeneities during the inflation era. The proposed framework is based on semiclassical gravity, in which one only focuses on quantizing the matter fields, but the spacetime metric is always treated in a classical manner. The objective collapse mechanism is based on the Continuous Spontaneous Localization (CSL) model, and we apply it to the wave function associated with the perturbations of the inflaton field. The collapse given by the CSL model provides a satisfactory mechanism of breaking the initial symmetries of the Bunch-Davies vacuum. Additionally, we obtain a primordial spectrum that has the same distinctive features as the standard one, and which is consistent with the observations from the Cosmic Microwave Background (CMB). The novel aspect in this work is that the constructed CSL model arises from the simplest choices for the collapse parameter and operator.
#263 |
Cosmic Rays at the Epoch of Reionization
Lautaro Carvalho
1
;
Leonardo Javier Pellizza
1
;
Gastón Javier Escobar
2
1 - Instituto de Astronomía y Física del Espacio, CONICET–UBA.
2 - Dipartimento di fisica e astronomia Galileo Galilei, Universitá degli studi di Padova.
Resumen:
Cosmic Dawn is an important open problem in Cosmology. The
radiation produced by the first galaxies would not have been
enough to maintain the ionization fraction of the IGM at
large scales, therefore complementary ionization agents
have been proposed, including cosmic rays (CR) that escape
from those galaxies. In this talk, we investigate the
ionization of the IGM produced by the electromagnetic
cascades initiated by CR electrons, emphasizing the
contribution of secondary photons, which has not been
extensively explored yet. We simulated the transport
of all the particles comprising the cascades and calculated
the rate of ionization and the distribution of energy
between the particles and the IGM. Our results show that
high energy electrons carry energy far away from the
source while ionizing the medium in their path, whilst
those with kinetic energies lower than a few keV cool
completely via ionization within a distance of kiloparsecs,
reinforcing the results of previous works and extending
their predictions to higher energy electrons and farther
distances from the source. In addition, we show for the
first time that photoionization by secondary photons
produced in high-energy cascades may contribute
significantly to the ionization of the IGM. This particular
result implies a significant ionization rate in the far IGM
that has not been considered by previous works. Finally,
we evaluate the ionization rate at any point in the IGM
in terms of the properties of the galaxy population
present during the Cosmic Dawn as predicted by
cosmological simulations of galaxy formation.
#415 |
Cosmic Mosaics: Investigating the Hues of Structure Formation in the Universe
Paul Eigenthaler
1
;
Thomas Puzia
1
;
Yasna Ordenes-Briceño
1
;
Bryan Miller
2
1 - Pontificia Universidad Católica de Chile.
2 - Observatorio Gemini Sur, NOIRLAB.
Resumen:
Our team is undertaking the Next Generation Fornax Survey (NGFS) in the optical u', g', and i' and the near-infrared (NIR) J and Ks filters.
The NGFS is a deep multi-wavelength survey that covers the entire Fornax galaxy cluster out to its virial radius (1.4 Mpc) using optical photometry obtained with DECam at Blanco/CTIO and NIR observations from VIRCAM at VISTA/ESO. We have recently published catalogs and characterizations of more than 600 dwarf galaxies in the central region of the cluster u',g',i'. The unprecedented depth of our survey allows us to study in detail the stellar populations of dwarf galaxies via color maps in high and low-density environments.
Galaxy colors arise from the dominant stellar populations within a galaxy and their ages. Hence, by examining the color of a galaxy one can determine the mix of stellar populations present in a stellar system. Studying color gradients and color maps within galaxies, i.e. the variations in color across their structures, reveals the spatial distribution of stellar populations within galaxies allowing for a more comprehensive understanding of the mechanisms that shape galaxy structures, their evolutionary paths, and the underlying physical mechanisms.
By comparing the colors of galaxies in different regions, such as dense galaxy clusters versus less crowded field regions, we can investigate the impact of environmental factors on the evolution of galaxies. Color variations across a galaxy cluster can provide insights into processes like ram-pressure stripping, tidal interactions, or galaxy harassment that influence the properties of member galaxies. Significant differences in color gradients or maps between cluster galaxies and field galaxies can provide insights into the mechanisms that quench star formation in dense environments. These measurements aid in understanding the physical conditions, evolutionary processes, and feedback mechanisms that shape galaxies and their star formation histories.
#443 |
Probing a protocluster candidate at $z \sim 4.5$ in
the COSMOS field
Mariana Rubet
1
;
Karín Ménedez-Delmestre
1
;
Thiago Signorini Gonçalves
1
1 - Observatório do Valongo - UFRJ.
Resumen:
The densest structures of the Universe formed at the knots of the cosmic web at high redshifts and constitute the present-day clusters of galaxies. They are nearly virialized systems, with a high density of gravitationally bound galaxies. The early stages of these structures are called protoclusters and they are the natural laboratories to observe the role of environmental effects on galaxy evolution. Protoclusters can be observationally identified by galaxy number density contrasts when compared to the field. In this work, we use submillimeter galaxies (SMGs), a population of dusty and distant starburst galaxies, which are expected to inhabit peaks of matter density, as targets for protocluster searches. We use combined wide-band and narrow-band optical photometry to identify Ly-alpha emitters (LAEs) around SMGs at $z\sim 4.5$ in the COSMOS field, as a means to identify typical star-forming galaxies that may trace the underlying structure containing our target SMGs. Using deep imaging, obtained by our team with the IMACS instrument on the Baade (6.5 m) telescope at the Las Campanas Observatory, we probe a physical scale of $\sim10 Mpc$ in size at $z=4.5$, consistent with protocluster scales. Our approach picks out line emitters as narrow-band excess objects. We denominate these objects as Ly-alpha candidates. We use additional IMACS spectroscopic data to confirm these candidates as bona fide LAEs and thus protoclusters members, eliminating low-redshfit interlopers. In comparisson with LAE density in the field, our preliminary results point to a mild excess in LAE density around SMGs at $z \sim 4.5$. These preliminary results are consistent with SMGs tracing typical moderate-mass structures of the Universe instead of the more massive ones, that grow into Coma-like clusters. SMGs may be thus an as-yet untapped population to understand the build-up of the more modest and more typical galaxy groups and clusters.
SALÓN ROJO (150)
10:50 - 11:30
COFFEE BREAK
Coffee and Poster Group II setup
11:30 - 13:00
G: Stars and Stellar Physics
Stellar Structure and Evolution I
#107 |
The stellar magnetism of the young Sun Iota-Horologii from the photosphere to its corona
Eliana Amazo-Gomez
1
1 - Leibniz Institute for Astrophysics Potsdam.
Resumen:
We conducted an extensive investigation into the stellar activity and variability of Iota-Horologii, a young star resembling our Sun. Our study employed a comprehensive multi-wavelength approach, combining data from various advanced instruments to obtain a comprehensive understanding of the star's behavior. To monitor the system, we utilized the ultra-stable spectropolarimeter/velocimeter HARPS at the ESO 3.6-m telescope for long-term spectropolarimetric observations. Additionally, we incorporated high-precision photometry data from the NASA Transiting Exoplanet Survey Satellite (TESS) and observations in the far- and near-ultraviolet spectral regions using the STIS instrument on the NASA/ESA Hubble Space Telescope (HST). Through the analysis of the gradient of the power spectra (GPS) derived from the TESS lightcurves, we were able to constrain the faculae-to-spot driver ratio (Sf/Ss) to 0.510 ± 0.023. This finding indicates that the stellar surface was primarily dominated by spots during the observation period. Furthermore, for the first time, we compared the photospheric activity properties obtained from the GPS method with a magnetic field map derived through Zeeman-Doppler imaging (ZDI) using simultaneous spectropolarimetric data. This comparative analysis provided valuable insights into the star's magnetic field and its influence on the observed activity. By employing different stellar activity proxies, we achieved a more comprehensive interpretation of the observed variability. Notably, we observed enhanced emission in the HST transition line diagnostics Civ and Ciii, suggesting the occurrence of a flaring event. Moreover, by analyzing TESS data simultaneously with the HST observations, we investigated the photometric variability during the precise moment of increased emission. This analysis allowed us to derive correlations between different observables, enabling us to probe the star's characteristics from its photosphere to its corona. Our extensive multi-wavelength campaign has provided a detailed understanding of the stellar activity and variability of Iota-Horologii.
#486 |
Does the Helium-flash add to the Lithium Budget of the Universe?
Julio Chanamé
1
1 - Pontificia Universidad Católica de Chile.
Resumen:
The existence of a small percentage of lithium (Li)-rich giants, defined as those showing A(Li) > 1.5 dex in their surfaces, is a decades old problem that challenges stellar evolution. More recently, based on Li data for large samples of evolved stars delivered by large spectroscopic surveys, the case has been made for Li-rich giants on a much more generalized scale, suggesting that all low-mass clump giants in the field, with typical levels 0 < A(Li) < 1.0 dex, are also enriched in Li beyond what is to be expected from standard stellar evolution. This would be an extraordinary turn of events for many branches of astrophysics, and has prompted works that explore new production channels of Li inside low-mass giants, particularly associated to the helium flash. Although proposed for all low-mass stars, if the mechanism really operates in nature, it may also have something to do with the classic problem of Li-rich giants. I will review the evidence and arguments for and against this possibility of a new Li production channel ubiquitous to all low-mass stars, and will show the results of a population synthesis analysis that, by accounting for the correct mass distribution of the progenitor stars of today's giants as informed by asteroseismology, argues against these claims.
#186 |
ALMA imaging of the complex, dynamical atmosphere of the AGB star W Hya at 20-milliarcsecond resolution
Keiichi Ohnaka
1
1 - Universidad Andres Bello.
Resumen:
The mass-loss mechanism in asymptotic giant branch (AGB) stars is not yet fully understood. It is crucial to spatially resolve the region within several stellar radii, where the stellar wind accelerates. We present 20-milliarcsecond resolution ALMA imaging of the well-studied AGB star W Hya in molecular lines of SiO, SO$_2$, H$_2$O, SO, HCN, TiO, AlO, and AlOH at 250--269 GHz, including masers from SiO, H$_2$O, and SO$_2$. The spatial resolution is three times finer than the W Hya's millimeter continuum angular diameter of ~60 mas, allowing us to spatially resolve the emission extending to $\sim$100 mas ($\sim$5 stellar radii) as well as inhomogeneous absorption over the stellar disk. The emission is irregularly shaped with a plume extending in the NNW, a tail extending in the SSE, an extended atmosphere elongated in the ENE-WSW direction, and many clumpy structures. The spatially resolved spectra of some lines show outflow velocities close to the local escape velocity. Surprisingly, we detected prominent emission over the stellar disk--instead of pure absorption as expected--in Si$^{17}$O, $^{30}$SiO, H$_2$O, and SO$_2$ lines. The surface emission seen in the Si$^{17}$O and vibrationally excited H$_2$O (v$_2$=2, 268 GHz) lines is particularly strong, indicating maser actions. The H$_2$O masers are confined within $\sim$50 mas (2.4 stellar radii), and the spatially resolved maser spectra are very broad, ranging from about -10 to 14 km~s$^{-1}$. This can be explained by outflowing and infalling motion induced by the stellar pulsation. The visible polarimetric images taken contemporaneously with our ALMA data reveal good agreement in the spatial distribution between the H$_2$O maser emission and clumpy dust clouds, lending support to the picture that the H$_2$O masers trace cool and dense pockects, where dust can form.
#044 |
Impact of evolutionary status on cool giant stellar activity levels
Missael Alejandro Hernández Huerta
1
;
Dennis Jack
1
;
Klaus-Peter Schroeder
1
1 - Universidad de Guanajuato.
Resumen:
The physical parameters of a sample composed of 28 late-type stars (spectral types G and K) were determined using recent parallaxes from Gaia DR3 together with analysis of the medium-resolution spectra (R approximately 21000) obtained in a dedicated observing program managed in the TIGRE telescope. Through comparisons with well-tested evolutionary tracks, mass values and stages of evolution were also derived, which in turn were put into perspective together with measurements of the S-index indicator of chromospheric magnetic activity. Four of the stars in the sample belong to the open cluster M41, so their coeval nature has made it possible to impose additional constraints to model their evolution, and thanks to this, the permanence of the activity exhibited during the relatively stable central helium-burning stage has been explored in good detail, whereas the non-cluster stars offer an insight into peripheral stages of evolution. Evidence points to a correlation between the state of evolutionary advancement within the horizontal branch and a sustained decline in activity, analogous to what has long been known to occur among cool main-sequence stars, and just as it was recently discovered to occur in the four Hyades K giants.
#061 |
Systematic method for identification of L-type variable brown dwarfs
Natalia Oliveros-Gomez
1
;
Elena Manjavacas
2
;
Daniela Bardalez-Gagliuffi
3
1 - Universidad de Guanajuato.
2 - Space Telescope Science Institute.
3 - Amherst College.
Resumen:
Most brown dwarfs show some level of photometric or spectrophotometric variability in different wavelength independently of their spectral type. Nevertheless, to date, we do not have an informed method to preselect the brown dwarfs that might show a higher variability amplitude for a thorough variability study. In Oliveros-Gomez, N., et.al. (2022), we designed and tested near-infrared spectral indices to preselect the most likely variable mid- and late-T dwarfs. In this work, we extend the method to preselect the most likely variable mid-L dwarfs (L4-L8). We used time-resolved near-infrared Hubble Space Telescope Wide Field Camera 3 spectra of a L6 dwarf, LP261-75B, to design our novel spectral indices. We compare the indices between them, which separate variable and non-variable spectra in different part of the index-index plots. In addition, we use a Machine Learning method to quantitively define areas where we most likely will find variable or non-variable brown dwarfs. We tested these spectral indices on 75 L4–L8 near-infrared SpeX/IRTF spectra, finding 30 new early- and mid-L variable candidates. We estimated the variability fraction of our sample as $\sim 54\%$, which agrees with the variability fractions provided by Metchev 2015 and Buenzli 2014 for L dwarfs. In addition, 11 of the 41 previously known variables in our sample of SpeX spectra are flagged as variable candidates by our indices. Similarly, 10 known non-variables in our sample are flagged as non-variable objects by our indices. These results suggest that our spectral indices might be used to find variable mid-L brown dwarf variables.
#399 |
Studying Radius Inflation on Low-Mass Stars Using Gaia DR3
Rocio Kiman
1
;
Timothy Brandt
2
;
Jacqueline Faherty
3
1 - California Institute of Technology.
2 - University of California, Santa Barbara.
3 - American Museum of Natural History.
Resumen:
Stellar age is a key fundamental property for understanding the history, evolution, and future of stellar populations, the Milky Way, and exoplanets. In order to estimate precise ages, we also need to understand the evolution of other fundamental properties such as mass, radius and effective temperature. However, current theoretical models over-predict effective temperatures, and under-predict radii, compared to observations of low-mass stars, or M dwarfs (radius inflation problem). Solving this problem is essential for current and upcoming NASA missions such as such as the Transiting Exoplanet Survey Satellite (TESS) and the Nancy Grace Roman Space Telescope which are expected to discover and characterize Earth-like exoplanets orbiting the nearest M dwarfs. Magnetic activity has been shown to be correlated with radius inflation for binary stars, but no clear correlation was found for single stars. In this talk I will present a model independent method to estimate stellar radii and how we used it to study the problem of radius inflation. Taking advantage of the precise photometry from Gaia DR3 we calibrated the surface brightness-color relation (SBCR) for low-mass stars. With the Gaia DR3 parallaxes and our SBCR we estimated radii for M dwarfs with measurements of the H$\alpha$ spectral line –the first Balmer line– which in emission is a magnetic activity indicator. We found that our model independent SBCR estimates accurate radii by comparing our results with the literature. In addition, we found that radius inflation is correlated to magnetic activity for single stars, and we calibrated the percentage of radius inflation as a function of H$\alpha$ emission and mass. This correlation could explain the difference between models and observations for M dwarf radii, and get us a step closer to understanding M dwarf evolution.
13:15 - 13:40
CONFERENCE PHOTO
CONFERENCE PHOTO @ THE BUILDING ENTRANCE (13:15)
15:00 - 16:00
Conferencia Divulgativa
Sede: Facultad de Ciencias, Salón de Actos. Dr. Alberto Bolatto: ¿Por qué se construyen nuevos radio observatorios y cómo funcionan?
SALÓN DORADO (120)
10:50 - 11:30
COFFEE BREAK
Coffee and Poster Group II setup
11:30 - 13:00
C: Education, Outreach and Heritage
Astronomy Teaching
Chair: Beatriz García
#385 |
Frontier Astronomy. Activities from the Perimeter Institute and the ICTP-SAIFR for the secondary classroom.
Martín Monteiro
1
1 - Universidad ORT Uruguay.
Resumen:
"Frontier Astronomy" and "Frontier Physics" are a series of activities for the secondary classroom that aims to share teaching techniques and strategies for the inclusion of modern and contemporary astronomy topics in the classroom, both in face-to-face classes and online. The activities are designed to be easily attached to regular physics or astronomy courses, without the need to change the curriculum.
\\
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The activities address current issues such as dark matter, exoplanets, the expansion of the universe, cosmology, black holes, gravitational waves, among others. The activities were developed by the renowned Perimeter Institute for Theoretical Physics of Canada, and translated and adapted into Portuguese and Spanish by the ICTP-SAIFR (South American Institute for Fundamental Research), a physics center associated with Abdus Salam ICTP (Trieste , Italy) and associated with the Institute of Theoretical Physics of the University of São Paulo, Brazil (IFT-UNESP).
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In this presentation we will make a brief summary of the didactic methodological proposal, and we will give some examples of concrete activities such as those that we have been presenting for two years, in collaboration with the ICTP-SAIFR, to secondary school teachers from all over Latin America, both virtual and face-to-face.
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References:
\\
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*Resources from the Perimeter Institute for teaching physics and astronomy in secondary schools, translated into Spanish. \\ (https://outreach.ictp-saifr.org/traducciones-al-espanol).
\\
*Frontier Physics in Spanish – Online 2021-2023. \\ (http://ictp-saifr.org/salaespanol).
\\
*Frontier Physics in Spanish – Face-to-face - Montevideo 2023 Edition. \\ (https://fisicamartin.blogspot.com/2023/05/ictp-saifr-fisica-de-border-edicion.html).
\\
*ICTP-SAIFR Summer Course for Secondary School Teachers – 2022 - Gravitational Waves and LIGO. \\ (https://outreach.ictp-saifr.org/cursoveraoprofessores/cursoveraoprofessores2022).
\\
* ICTP-SAIFR Summer Course for Secondary School Teachers – 2023 - Cosmology. \\ (https://fisicamartin.blogspot.com/2023/01/iii-curso-de-verano-del-ictp-saifr-2023.html).
#488 |
A digital game to teach stellar nucleosynthesis: design and student feedback
Crediana Chris de Siqueira
1
;
Newton Figueiredo
1
;
Adhimar Flávio Oliveira
1
;
Milady Renata Apolinário da Silva
1
;
Marcos Antonio Fonseca Faria
2
1 - Universidade Federal de Itajubá.
2 - Laboratório Nacional de Astrofísica.
Resumen:
The use of digital technologies combined with an interdisciplinary approach that connects the periodic table to Astronomy can provide students a broader and more meaningful understanding of the stellar nucleosynthesis of the chemical elements, thus becoming an effective strategy to motivate them to learn this subject. This work presents an educational digital game written in Python titled "The Periodic Table According to Cosmochemistry" (PTAC), designed to playfully address the synthesis of chemical elements in the context of Astronomy. Therefore, this work presents the development of the game and an analysis of its effectiveness, based on the feedback of 53 players who tested the game. The game was played by students enrolled in Elementary School, High School, and Higher Education classes, aiming to obtain a wide diversity of student feedback. Questionnaires containing open-ended and multiple-choice questions were used to collect data from these students. These questionnaires were made available both digitally and in printed form and data analysis was conducted qualitatively and quantitatively. The results obtained provided evidence that this game is an effective educational resource, capable of motivating students, promoting learning, and providing a positive gaming experience. We also present the strengths and weaknesses of the game, as well as possible future improvements and the optimal age range for its application as a teaching resource. Based on the findings of this research, the use of educational digital games, such as PTAC, can be a promising approach to improve the teaching of the stellar nucleosynthesis of the chemical elements. By integrating Chemistry, Astronomy, and digital technologies, educators have the opportunity to spark students' interest and encourage their pursuit of knowledge in a more meaningful way.
#533 |
Teaching astronomy with ASTROLAB at PUCP
Myriam Pajuelo
1
;
Michele Gerbaldi
2
;
Aldo Panfichi Sanborn
1
;
Nicole van der Bliek
3
1 - Pontificia Universidad Católica del Perú.
2 - IAP (Institut d\textquotesingle Astrophysique de Paris).
3 - NSF\textquotesingle s NOIRLab.
Resumen:
We present the experience of teaching an astronomy course at the introductory level at the Pontifical Catholic University of Peru (PUCP). Students attend theory sessions alongside practical experiences observing remotely using the Las Cumbres Observatory 40 cm telescopes. This is done using the ASTROLAB (Starlight in the university lab) tutorial, a project of the Office of Astronomy for Development (OAD) of the IAU. With this, we try to make up for the few opportunities that undergraduate Peruvian students have to do observational astronomy, due to the few astronomical facilities that exist in the country.
The students are introduced to scientific research methods as they go through the same steps astronomers do when preparing and doing an observing program. Students learn how to plan observations, submit proposals, process their data and analyze their results using astronomy software and Virtual Observatory (VO) tools on images obtained from remote telescopes of Las Cumbres Observatory. This teaches students to develop teamwork abilities, understand the complexity and ambiguity of empirical work, develop practical skills, error analysis, defend their results both in written and oral form, and most importantly: develop critical thinking.
#188 |
La Serena School of Data Science: Applied Tools for Data-Driven Sciences
Valeria Mesa
1
;
Guillermo Damke
2
;
Amelia Bayo
3
;
Matthew Graham
4
;
Dara Norman
2
;
Mauricio Cerda
5
;
Francisco Förster
5
;
Camila Ibarlucea
2
1 - ULS/AURA, IANIGLA.
2 - NOIRLab.
3 - ESO.
4 - Caltech.
5 - Universidad de Chile.
Resumen:
The volume and complexity of astronomical data continues to grow as the current generation of surveys come online (PanSTARRS, Dark Energy Survey, VISTA). Astronomers will need to work with giga, tera and even petabytes of data in real time (LSST). This poses the challenges of developing and using new tools for data discovery, access, and analysis. At the same time, there are new opportunities for interdisciplinary research in applied mathematics, statistics, machine learning, crowd-sourcing, etc. Astronomy provides a sand-box where scientists can come together from diverse fields to address common challenges within the "Big Data" paradigm. In response, since 2013 the AURA/NOIRLab observatory has implemented the “La Serena School for Data Science: tools for Data-Driven sciences”. In this contribution we present our initiative, which is developed annually at the AURA campus in La Serena, Chile. Each August, the school receives 32 students and 10 expert professors for 10 days, following an intensive program of introductory classes with an important component of hands-on learning. This is materialized mainly by the development of group projects, where students solve complex problems in groups, applying what they have learned and guided by the teachers. Participants come from various countries such as the US (NSF-funded), Chile, and other Latin American countries such as Ecuador, Brazil, Mexico or Colombia. Students from different disciplines are encouraged to participate, including (but not limited to) astronomy, physics, computer science, statistics, mathematics, biology medical informatics. Finally, we discuss the opportunities that this school can offer to students in Latin American institutions.
#059 |
Remote/Robotic Observations in the classroom: The Physics and Astronomy Undergraduate/Graduate courses at UNAM
Hector Hernandez-Toledo
1
;
Luis A. Martinez-Vazquez
1
;
Wenceslao Santiago-German
2
1 - Instituto de Astronomia, UNAM.
2 - Escuela Nacional Preparatoria, UNAM.
Resumen:
More than 360,000 students at UNAM stopped attending regular courses due to the COVID-19 pandemic. In addition, it is known that a fraction of the students abandon their studies for various reasons, including economic ones. To reduce the impact of such abandonment we proposed to reinforce and make more attractive the strategies of remote or online learning. We present the results of a joint project in collaboration with the National Optical Observatory at San Pedro Martir, Mexico (OAN-SPM) and the Institute of Astronomy academic campus in Mexico City aiming to attack this problem that consisted of two parts:
1. We proposed opening the access to the remote 0.84m telescope of the OAN-SPM and its instrumentation for the basic physics and astronomy courses, via internet and eventually at the classroom site. We revised the curricula of various courses looking to innovate on the teaching and learning and exposing the students to a more meaningful and profound knowledge covering concepts and topics. Our goal is to gradually replace some of the in classroom practices and
traditional exercises with new interactive practices with the participation of teachers.
2. We complement the impact of our proposal by generating new excercises exploiting the content of digital databases of various international astronomical projects such as the Sloan Digital Sky Survey IV-V.
#529 |
Analog Simulation to explore and teach exoplanetology concepts
Johan Nicolás Molina Córdoba
1
;
Johana Murcia Rocha
2
;
Carlos Andrés Ospina Castillo
3
1 - Observatorio Astronómico Nacional, Universidad Nacional de Colombia; Orbitamautas Astronomy Group.
2 - Orbitamautas astronomy group.
3 - Universidad Pedagógica Nacional; Orbitamautas Astronomy Group.
Resumen:
This work presents a proposal for analog simulation enabling the generation of light curves for simulated transit events of exoplanetary systems in a straightforward manner. The setup is established for two exoplanetary systems, referred to as System A and System B, yielding a size estimation error margin of 1.5\% for System A and 4.25\% for System B. The frequency spectrum of the time series signals from both systems provides a reliable estimation of their respective orbital periods within the setup. The high sampling rate of the light sensor integrated into an average mobile phone (100 ms) allows for a scaling of 1 second = 1 day in testing, aligning the framework of the proposed experiment with the scientific data used in the study of exoplanetary light curves. Due to the uncertainty associated with the measured fluxes for each obtained light curve ($\approx$1e-7 lx), the setup proves efficient and could be employed to undertake more rigorous investigations, accounting for improved analytical criteria and better-controlled laboratory conditions. Furthermore, the experimental setup has sparked considerable interest in pilot test's due to its interactivity, rendering it an enriching educational resource. This analog simulation presents an excellent opportunity to impart captivating concepts concerning exoplanets and the methods astronomers employ to study these distant systems. The light curve generated during the transit of exoplanets furnishes vital information about their physical and orbital characteristics. Through this low-cost educational tool, students can explore and comprehend the measurement of the semi-major axis, orbital period, and exoplanet-to-star size ratio of the simulated systems. Finally, the setup facilitates the formulation of inquiries that foster learning and understanding of key topics related to exoplanets and light curves, stimulating curiosity and active engagement in the educational process.
13:15 - 13:40
CONFERENCE PHOTO
CONFERENCE PHOTO @ THE BUILDING ENTRANCE (13:15)
16:30 - 17:30
Conferencia Divulgativa
Sede: Intendencia de Montevideo, Salón Dorado. Dr. Felix Mirabel: “Agujeros Negros en el Universo”
