SALÓN AZUL
09:00 - 09:50
Plenary Review Talk
Invited Speaker:
Laurence Sabin
- Instituto de Astronomía (Ensenada), UNAM
(México)
[cv]
Laurence Sabin
Instituto de Astronomía (Ensenada), UNAM
Curriculum Vitae:
La Dra Sabin completó su doctorado en la Universidad de Manchester (Jodrell Bank Center for Astrophysics, UK) y llevó a cabo una parte de esos estudios en el Instituto de Astrofísica de Canarias (Tenerife). Su especialización se centra en el análisis de estrellas evolucionadas de masa intermedia (como nebulosas planetarias, estrellas simbióticas, novas …) y a veces de masa alta (e.g. remanentes de supernova) tanto para su detección y caracterización usando grandes catastros de cielo, como para el estudio de los campos magnéticos asociados a dichos objetos. La Dra. Sabin es miembro del Instituto de Astronomía de la UNAM en Ensenada, donde desempeña su labor como investigadora. También es parte de varios grupos de investigación a nivel nacional (Grupo de Estudio de Estrellas evolucionadas del IA-Ensenada, Grupo Nacional de Polarización en Astronomía), así como de grupos internacionales (Consorcio EGAPS, Consorcio SAINT-EX y Grupo de investigación de nebulosas alrededor de estrellas evolucionadas).
Chair: Julio Carballo-Bello
#024 |
From Post-AGBs to White Dwarfs: Exploring the Fascinating Evolution of Intermediate Mass Stars
Laurence Sabin
1
1 - Instituto de Astronomia, UNAM (Mexico).
Resumen:
I will present the latest studies on the evolution of intermediate mass stars, specifically from the post-AGBs to white dwarf phase, all of which are shedding new light on these fascinating astronomical objects. It is known that intermediate mass stars undergo complex physical (and chemical) processes as they evolve from post-AGBs to white dwarfs, with significant changes in their physical properties occurring during different stages of their evolution. I will present different combinations of observational data and theoretical models used to investigate the various phenomena that occur during this evolution, such as mass loss and the formation of planetary nebulae. These studies are essential for advancing our understanding of the life cycle of stars and their contribution to the chemical enrichment of the universe. The findings from these studies may also have significant implications for our understanding of the formation and evolution of planetary systems around other stars. Overall, these latest studies provide valuable insights into the complex and intriguing processes that occur during the evolution of intermediate mass stars.
09:50 - 10:20
Plenary Target Talk
Invited Speaker:
Bruno Dias
- Instituto de Astrofísica, Universidad Andrés Bello
(Chile)
[cv]
Bruno Dias
Instituto de Astrofísica, Universidad Andrés Bello
Curriculum Vitae:
Bruno Dias is a professor at the Institute of Astrophysics, Universidad Andrés Bello (UNAB), Chile, with 46+ refereed publications (2010-2023). Bruno got a PhD from Universidade de São Paulo, Brazil in 2014, including an ESO studentship, which gave him two prizes for best thesis at the same university. He worked as a postdoctoral researcher at Durham University, UK and Universidad Andrés Bello, Chile, besides being awarded an ESO fellowship. He has been an independent researcher of the Instituto de Alta Investigación, Universidad de Tarapacá, Chile. His main research line is on stellar populations of the Milky Way and Local Group galaxies, in particular studying their star clusters. Bruno is the PI of the VISCACHA survey that is the project with more accumulated nights at SOAR telescope, using adaptive optics to obtain deep and spatially resolved photometry of star clusters in the Magellanic Clouds, and spectroscopic follow-up with GMOS/Gemini. The big goal of VISCACHA is to trace the past chemo-dynamical history of the Magellanic Clouds using their star cluster population as well as to analyse the internal structure, kinematics and stellar populations within individual clusters. Among his main personal objectives, Bruno wishes to produce high-level science with Latin America astronomers, which is evident with the VISCACHA team of about 40 members in Brazil, Chile, Argentina, México, and 12 VISCACHA or VISCACHA-related refereed papers since 2019 and growing, as well as active research grants in Chile, Brazil, and fund raising for scientific meetings. Bruno also created the ESO Python Boot Camp and gave the first steps to move ESO Paranal systems to Python. Bruno co-created, directed and taught in the Diplomado en Astronomía General at UNAB, the only in Chile. Bruno is also a member of the VVVX, SDSS-V, SPLUS survey teams, and MOSAIC/ELT science team. Last but not least, he is the current president of Chilean Astronomical Society (2023-2024) and president of the IAU-NCA in Chile, working to develop Astronomy in Chile, which hosts more than 50% of the global collecting area from ground-based telescopes.
Chair: Julio Carballo-Bello
#108 |
The VISCACHA survey: The Magellanic Clouds and their star clusters
Bruno Dias
1
1 - Instituto de Astrofísica, Universidad Andrés Bello, Chile.
Resumen:
The Large and Small Magellanic Clouds (LMC and SMC) are the two most massive satellite galaxies surrounding the Milky Way. They are likely in their first infall to our Galaxy and have just passed pericentre. Their orbit has been dragging a 200 degrees-long gas trailing stream and also a leading gas structure. The LMC-SMC pair has been interacting to each other with multiple encounters throughout their lives, which heavily impacted their structure, triggered star formation and boosted star cluster dissolution. The chemical evolution of these two galaxies is much less efficient than expected, and they are different in various regions of the SMC for example. Understanding this complex history requires a lot of precise chemical and kinematic information as a function of time and space combined to sophisticated chemo-dynamical models. The star clusters are excellent fossils because we can measure their 3D position, 3D velocities, age, metallicity, internal structure, and they trace the different regions of the LMC and SMC, as well as covering a large age range. In this talk, I will briefly review the topic, present the VISCACHA survey that I lead involving astronomers from a handful of Latin America countries producing high-level science with star clusters in this context and a dozen papers so far.
10:20 - 11:00
COFFEE BREAK
11:00 - 12:30
F: Planetary Systems & Astrobiology
Exoplanetary atmospheres and composition
Chair: Carolina Agurto
#492 |
Simulation of potentially habitable environments on the surface of exoplanets
Paola Cunha
1
;
Luan Ghezzi
1
;
Douglas Galante
2
;
Evandro Silva
2
;
Fabio Rodrigues
2
;
Ana Carolina Carvalho
2
;
Junia Schultz
3
;
Alexandre Rosado
3
;
Amanda Bendia
2
1 - Valongo Observatory.
2 - University of Sao Paulo.
3 - King Abdullah University of Science and Technology.
Resumen:
M-dwarfs comprise 75\% of the stars in the Milky Way and also host a large fraction of the potentially habitable exoplanets. However, the high levels of stellar activity are a challenge in a biological conext. They exhibit frequent and intense flares, exposing their planets to high levels of ultraviolet (UV) radiation. This radiation is crucial for biological systems, but excessive exposure can cause damage to important cell structures. Thus, the aim of this work is to investigate whether life could withstand the environmental conditions of planets orbiting M-dwarfs. For our analysis, we choose, Proxima Centauri b, an exoplanet discovered in 2016 and recently confirmed. It has 1.17 times the mass of Earth and is located in the habitable zone of the system, which is a favorable characteristic for life as we know it. To obtain the results, we performed irradiation experiments with the yeast Rhodotorula collected in Diamantina, MG. The first experiment was performed with a tubular lamp that covers only the UVC region. The second experiment was conducted with a continuous spectrum lamp that covers the entire UV range. The last experiment was carried out in the Space and Planetary Simulation Chamber (AstroCam) to simulate hypothetical conditions on the surface of Proxima b. We simulated atmospheres of 100\% CO$_2$ and primitive Earth (80\% CO$_2$ and 20\% N$_2$), with a pressure of 1000 mbar, and the continuous spectrum lamp coupled to AstroCam. The results showed that irradiations using the continuous spectrum lamp are more lethal than the tubular lamp. Additionally, we observed that cells resisted to a dose of 60000 J/m$^2$ for the UVC lamp. Assuming an average flux value for the flares on Proxima b (7 W/m$^2$), this dose would be reached in about 2.38 hours. Our results provide important data to guide studies searching for biosignatures on exoplanets.
#140 |
Physical Properties and Chemistry of Dust Clouds in Extrasolar Atmospheres
Genaro Suárez
1
;
Johanna Vos
2
;
Stanimir Metchev
3
;
Jacqueline Faherty
1
;
Kelle Cruz
4
1 - American Museum of Natural History.
2 - Dublin Institute for Advanced Studies.
3 - The University of Western Ontario.
4 - Hunter College.
Resumen:
Clouds influence most aspects of extrasolar atmospheres and, therefore, shape their emergent spectra. Studying these clouds is essential to learn about the thermal structure, composition, detectability, and habitability of planetary atmospheres. In anticipation of JWST observations of cloudy exoplanet atmospheres, we analyze all Spitzer mid-infrared spectra of ultracool dwarfs and find the following results, which constitute a paper series: 1) silicate clouds are near ubiquitous in (L-type) extrasolar atmospheres, 2) these clouds form, then thicken, and sediment in the 2000-1300 K effective temperature range, 3) young atmospheres are cloudier due to a slower settling of dust clouds, 4) variable objects are more likely to have higher dust cloud opacity, and 5) equatorial latitudes are cloudier compared to the poles. These results significantly grow our knowledge of the formation, composition, and evolution of dust clouds in extrasolar atmospheres and partially explain the spectral diversity observed in directly-imaged exoplanets and brown dwarfs by invoking their viewing geometry. Our ongoing JWST higher resolution and SNR observations of extrasolar atmospheres will further inform about the physical properties and chemistry of dust clouds.
#168 |
The Composition of Beta Pic Molecular Cloud as traced by HD 181327 and the Formation of Beta Pic b
Henrique Reggiani
1
;
Jhon Galarza
2
;
David K. Sing
3
;
Kevin C. Schlaufman
3
;
Brian F. Healy
4
;
Andrew McWilliam
2
;
Joshua D. Lothringer
5
1 - NOIRLAB.
2 - The Carnegie Observatories.
3 - William H. Miller III Department of Physics and Astronomy, Johns Hopkins University.
4 - School of Physics and Astronomy, University of Minnesota.
5 - Department of Physics, Utah Valley University,.
Resumen:
Protoplanetary disk and giant planet formation models have been interpreted to suggest that a giant planet's atmospheric abundances can be used to infer its formation location in its parent protoplanetary disk. It has been reported that the hot Jupiter $\beta$ Pictoris $b$ has subsolar carbon and oxygen abundances ratios. Assuming solar carbon and oxygen abundances for its host star $\beta$ Pictoris, $\beta$ Pictoris $b$'s atmospheric carbon and oxygen abundances possibly indicate that it slowly formed via core-acretion somewhere between the disk's H$_{2}$O and CO$_{2}$ ice lines. However, due to $\beta$ Pic's photospheric parameters, it is notoriously difficult to directly infer carbon and oxygen abundances from $\beta$ Pictoris. We characterize star HD 181327, part of $\beta$ Pictoris's moving group, and argue that its stellar abundances are the best way to infer the elemental composition of the protoplanetary disk from which $\beta$ Pictoris $b$ was formed. We also perform our own retrieval of $\beta$ Pic $b$. Our inferred C/O abundances for HD 181327 and $\beta$ Pic $b$ corroborates the scenario outlined by previous studies, showing $\beta$ Pic $b$ formed via core-accretion beyond the water ice line. We reinforce that giant planet atmospheric abundance ratios can only be meaningfully interpreted relative to the possibly non-solar mean compositions of their parent protoplanetary disks.
#217 |
A modern view of giant planet interiors
Yamila Miguel
1
1 - Leiden Observatory / SRON.
Resumen:
We are at a unique time to study giant exoplanets. With more than 5000 exoplanets found and facilities like JWST that provide unprecedented data on their atmospheres, we moved from an era of discovery to an era of exoplanet characterisation. On the other hand, extremely accurate measurements by Juno and Cassini missions, make this an exceptional time to combine the detailed information on the solar system's giant planets and the large amount of data from exoplanets to get a better understanding of planetary physics and a better comprehension on planet formation and evolution.
Because the giant planets in our solar system are and will remain to be the touchstone to understanding the detailed processes that happen in these worlds, in this talk I will present my recent study on the amount and distribution of heavy elements in Jupiter’s interior and I will also discuss the implication of this study on giant exoplanets, presenting some unpublished work towards a better characterisation of giant exoplanet interiors using JWST data.
#456 |
Effects of Pressure Dependency in Exoplanetary Atmospheric Retrieval
Aline Novais
1
1 - Observatório do Valongo, Universidade Federal do Rio de Janeiro.
Resumen:
Although the analysis of exoplanet atmospheres has become one of the most pertinent topics within planetary sciences, characterising these objects directly from their spectra is still a challenge. To interpret the observed spectrum of an exo-atmosphere, one can apply a technique known as atmospheric retrieval, i.e. fitting a model to this data in order to infer the properties of the atmosphere, such as temperature, chemical composition, and presence of clouds. This work considers a retrieval framework which includes H2O as the main molecular opacity source, and optional opacity features such as additional molecules (e.g. CH4, CO2, CO), collision-induced absorption (CIA), Rayleigh scattering, and clouds. Furthermore, our retrieval code accounts for a non-isobaric transit chord, setting atmospheric opacity sources to a full pressure dependency. We perform non-isobaric retrievals in 38 Hubble Space Telescope Wide Field Camera 3 (WFC3) near-infrared transmission spectra to establish how the variation of pressure affects the estimation of atmospheric parameters. Our results show that, for WFC3 wavelength range and resolution, mainly H2O-only cloud-free and constant/grey cloud atmospheres are retrieved. We compare our findings with previous analyses in the literature, concluding that Rayleigh scattering is negligible in most of our retrievals, except in the ones where shorter-wavelength WFC3 data is available. On the other hand, CIA is strongly dependent on pressure, therefore helping set the H2O abundance, which is unclear in the former isobaric studies. Additionally, we acknowledge the degeneracy between molecular abundances and the reference parameter (i.e. where the atmosphere is optically thick), as pointed out by previous studies, may be broken for cloud-free fits, but is still indirectly present in cloudy results. Finally, we suggest new approaches that could help identify additional atmospheric features imprinted in the spectra, considering data in complementary wavelengths, as well as retrieval analyses using higher-quality James Webb Space Telescope spectra.
#173 |
A comprehensive homogeneous investigation of orbital ephemeris and transmission spectrum of WASP-19 b.
Anitha Raj Rajkumar
1
;
Jeremy Tregloan-Reed
1
1 - Universidad de Atacama.
Resumen:
Exoplanets with ultra-short periods (P < 1 day) might experience orbital decay due to the tidal dissipation effect with the host star. My current work allows verification of the orbital ephemeris of the WASP-19b with the availability of long-term high-precision photometric and spectroscopic data including 20 unpublished transits from the Danish telescope. This place limits on the modified tidal quality factor Q’*.
The same data allows for a detailed study of the atmospheric properties of WASP-19b, via transmission photometry and spectroscopy. WASP-19A is an active host star with its surface littered with starspots, which if not correctly modeled, systematics are introduced into the transit timing measurements and transit depth, which latter affects the exoplanetary transmission spectrum. Additionally the signal from stellar inhomogeneities can outweigh the signal from planetary spectral characteristics (Rackham, B., V., et al. 2022, arXiv, 220109905, submitted to RAS Techniques and Instruments as invited review.). Therefore, to perform a full and complete orbital ephemeris study of WASP-19b requires the modeling of detected starspots. Incidentally, failing to model both occulted and unocculted starspots can skew measurements in the planetary radius affecting the broadband transmission spectrum. Using the transit-starspot model, PRISM we perform the most complete, detailed, homogeneous analysis of all available data to estimate Q’* and study the atmospheric properties of WASP-19b with the help of ground- and space-based archival data.
12:30 - 14:30
LUNCH
14:30 - 15:20
Plenary Review Talk
Invited Speaker:
Rodrigo Díaz
- Universidad de San Martín
(Argentina)
[cv]
Rodrigo Díaz
Universidad de San Martín
Curriculum Vitae:
Rodrigo Díaz es investigador en el Instituto de Ciencias Físicas, de doble dependencia UNSAM / CONICET. Es especialista en el análisis de datos astronómicos para la detección y caracterización de exoplanetas. Además, es profesor en la Universidad Nacional de San Martín, donde se desempeña como director de la Lic. en Ciencia de Datos.
Chair: Daniela Lazzaro
#606 |
Extrasolar planet discovery and characterisation in the era of James Webb and the data revolution
Rodrigo Díaz
1
1 - Instituto de Ciencias Físicas (ICIFI; CONICET) / Univ. de San Martín.
Resumen:
In the pursuit of unraveling the mysteries of our universe, the discovery and characterisation of extrasolar planets have been among the most captivating endeavours in modern astronomy. The processes of exoplanet formation and evolution have come into focus thanks to nearly 30 years of observational and theoretical efforts.
Amid this backdrop of discovery and exploration, the James Webb Space Telescope (JWST), with its spectroscopic and imaging instruments working across the infrared spectrum with unrivalled capabilities, is already providing an unprecedented window into the atmospheres of exoplanets, allowing us to probe their physical and chemical properties. This in turn sheds light on many aspects of the formation and evolution of planets.
At the same time, the data revolution is changing radically the way research is done in diverse fields of the physical sciences from particle physics to molecular dynamics to cosmology. The realm of exoplanetary science is no exception. Advancements in data science and machine learning are becoming indispensable tools to fully exploit the available data sets and to prepare for future instruments.
Indeed, exoplanetary science resides at the intersection of two waves of transformation, where the dynamic interplay between cutting-edge observational technology and data-driven analytical tools promise to usher a new era of discoveries and revelations.
In this talk, I present and overview of the latest advances in the field, with particular emphasis in the areas where the combination of data-driven techniques and new instrumentation has the potential to drastically advance the field. I also present part of the work conducted at the University of San Martín, where an interdisciplinary team of physicists, astronomers and computer scientists is harnessing the power of big data and innovative analytical techniques to extract valuable insights from an ever-expanding dataset.
15:20 - 15:50
Plenary Target Talk
Invited Speaker:
María Paula Ronco
- Instituto de Astrofísica de La Plata
(Argentina)
[cv]
María Paula Ronco
Instituto de Astrofísica de La Plata
Curriculum Vitae:
María Paula Ronco es doctora en Astronomía egresada de la Universidad Nacional de La Plata, Argentina. Fue investigadora postdoctoral NPF y FONDECYT en el Instituto de Astrofísica de la Pontificia Universidad Católica en Chile y actualmente es Investigadora Asistente de Conicet en el Instituto de Astrofísica de La Plata y docente en la UNLP. Es integrante del Grupo de Astrofísica Planetaria e Investigadora adjunta del Núcleo Milenio de Formación Planetaria en Chile. Se especializa en el estudio teórico de la evolución de discos protoplanetarios y en la formación y evolución de sistemas planetarios mediante simulaciones numéricas.
Chair: Daniela Lazzaro
#264 |
Disk evolution and planet formation around intermediate mass stars: The first step towards understanding white dwarf pollution
María Paula Ronco
1
;
Matthias R. Schreiber
2
;
Eva Villaver
3
;
Octavio Miguel Guilera
1
;
Marcelo Miguel Miller Bertolami
1
1 - Instituto de Astrofísica de La Plata.
2 - Departamento de Física, Universidad Técnica Federico Santa María.
3 - Centro de Astrobiología (CAB), CSIC-INTA,.
Resumen:
The study of protoplanetary disk evolution and theories of planet formation has predominantly concentrated on solar (and low) mass stars since they host the majority of the confirmed exoplanets. Nevertheless, the confirmation of numerous planets orbiting stars more massive than the Sun (up to 3Msun) has sparked considerable interest in understanding the mechanisms involved in the formation of exoplanets around such stellar objects. As intermediate mass stars are the progenitors of the currently observed white dwarf population, understanding planet formation around these stars is most likely related to the fact that 30 - 50 per cent of the known white dwarf population show signs of atmospheric pollution by planetary debris.
In this talk I will describe our latest results on protoplanetary disk evolution simulations which we developed as a first step towards a better understanding of planet formation around 1-3Msun stars. We investigated how the gas component of protoplanetary disks evolves considering different disk initial conditions such as different viscosities and initial masses of the disk, and by taking into account the effects of stellar evolution which become relevant as the mass of the central star increases. Our findings confirm that in general disks around more massive stars evolve faster than those around low-mass stars, except if low viscosities are considered. Our simulations also reveal four distinct evolutionary pathways for the gas component not reported before, which likely have a substancial impact on the dust evolution and thus on planet formation. I will also discuss these implications and present preliminar results of planet formation simulations around 1-3Msun stars.
15:50 - 16:20
Plenary Target Talk
Invited Speaker:
Tabaré Gallardo
- Universidad de la República
(Uruguay)
[cv]
Tabaré Gallardo
Universidad de la República
Curriculum Vitae:
Profesor Titular del Departamento de Astronomia del Instituto de Fisica de la Facultad de Ciencias (Udelar, Uruguay) dedicado a la dinamica de sistemas planetarios y de cuerpos menores, con enfasis en resonancias orbitales.
Chair: Daniela Lazzaro
#303 |
Orbital resonances in planetary systems
Tabare Gallardo
1
1 - Facultad de Ciencias, Udelar.
Resumen:
Orbital resonances are dynamic mechanisms characterized by some strength capable of overcoming other perturbations, managing to keep the planetary systems captured in the resonance.
There are two types of orbital resonances: mean motion resonances and secular resonances.
We will discuss here the mean motion resonances. They are located at some specific values of the semimajor axes but they occupy a non-negligible region of the semimajor axis space, which crucially depends on the orbital eccentricities as can be seen in the structures shown in the figure corresponding to the mutual resonances in the HD74156 system. The existence of a certain resonant width added to the fact that there are mechanisms that lead to resonances (through orbital migration for example) makes resonant systems frequent.
Several analytical models that have been proposed describe very well the resonant dynamics for low eccentricities and coplanar orbits, but when we go to inclined and eccentric orbits, the models become very complex, since they depend on long series expansions specific to each resonance, or they cannot be applied at all. The GBG21 semianalytical model (Gallardo, Beauge, Giuppone, 2021, A\\&A, 646, A148) is applicable in principle to all resonances without restrictions, it is especially good for eccentric and inclined systems and provides us with all the information that characterizes a resonance: location and width in semimajor axis, equilibrium points, libration periods, strengths and moreover, it describes very well the dynamical evolution in the vicinity of a resonance. This model also has the advantage of being implemented through a code that can be used without having to be a specialist in the subject. In this work we show how to apply the model to some planetary systems and how to interpret the results.
We will also briefly discuss the more complex problems of three-body resonances and resonant chains.
16:20 - 17:00
COFFEE BREAK
17:00 - 18:30
F: Planetary Systems & Astrobiology
Planetary Formation and Dynamics
Chair: Adrian Rodríguez
#349 |
Stellar Activity or a Planet?
Revisiting dubious planetary signals in M-dwarf systems
Daniela González
1
;
Nicola Astudillo-Defru
2
;
Ronald Mennickent
1
1 - Universidad de Concepción.
2 - Universidad Católica de la Santísima Concepción.
Resumen:
M dwarfs often exhibit magnetic activity that can affect radial velocity (RV) measurements inducing periodic signals that can be misinterpreted as planetary signals. GJ581, an M dwarf hosting a multiplanetary system, shows a reported stellar rotation period of 132 $\pm$ 6.3 days that closely matches the twice and four times the orbital periods of the d (66.6 days) and g (36.6 days) planets, respectively. This similarity raises questions about whether these signals are planets or artifacts of stellar rotation.
In this study, we reanalyze the RV time series of GJ581 using publicly available data from HARPS, HIRES and CARMENES, as well as stellar activity indicators. Our aim is to confirm or dismiss the existence of these dubious planetary signatures in the GJ581 system. We computed a Generalized Lomb-Scargle periodogram analysis on the RVs to identify periodic signals. Moreover, we used a Keplerian fit to model the RV time series and Gaussian Process (GP) regression to model the stellar activity indicators. Our analysis shows a stellar rotation period of 132.24 $^{+1.82}_{-1.71}$ days, which aligns with previous studies. However, the RVs temporal stability analysis suggest that the signal d may not be attributed to a planet. Further statistical analysis, such as a simultaneous fit of the RVs with a Keplerian model and the activity indices with a GP, is required to determine the more favorable model for the data. Once our analysis is consistent with previous work, it will be applied to other M dwarfs.
#566 |
Exploring protoplanetary disk evolution via magnetically driven winds
Elisa Castro Martínez
1
;
Octavio Miguel Guilera
2
;
Jose Luis Gomez
2
;
Sebastián Bruzzone
1
;
Julia Venturini
3
1 - Facultad de Ciencias, Universidad de la República, Montevideo.
2 - Instituto de Astrofísica de La Plata, Argentina.
3 - Department of Astronomy, University of Geneva, Switzerland.
Resumen:
Magnetically driven disk winds (MHD winds) are thought to be one of the main processes involved in the evolution and dispersal of protoplanetary disks, not only affecting the net accretion rate and gas mass loss but also introducing qualitative differences in the disk evolution in contrast with the classic alpha disk model, potentially impacting the formation and architecture of debris disks and planetary systems. We performed numerical simulations for the evolution of gas and dust protoplanetary disks, including viscous dissipation, X-ray photoevaporation and MHD winds, for different stellar masses and initial conditions of the disks. We studied the qualitative features observed in different disks and performed population synthesis in order to constrain the parameters that better reproduce the observables. Different disk wind regimes and viscous alpha parameters were implemented. Our presentation will focus on the obtained results and their correlation with key observables, such as gas accretion rates and lifetimes. The possible implications of these findings for planet and debris disk formation will also be discussed.
#122 |
Feedback-limited accretion: variable luminosity from growing planets
Matías Gárate
1
;
Jorge Cuadra
2
;
Matías Montesinos
3
;
Patricia Arévalo
4
1 - Max-Planck-Institut für Astronomie.
2 - Universidad Adolfo Ibáñez.
3 - Universidad de Viña del Mar.
4 - Universidad de Valparaíso.
Resumen:
Planets form in discs of gas and dust around stars, and continue to grow by accretion of disc material while available. Massive planets clear a gap in their protoplanetary disc, but can still accrete gas through a circumplanetary disc. For high enough accretion rates, the planet should be detectable at infrared wavelengths. As the energy of the gas accreted on to the planet is released, the planet surroundings heat up in a feedback process. We aim to test how this planet feedback affects the gas in the coorbital region and the accretion rate itself. We modified the 2D code FARGO-AD to include a prescription for the accretion and feedback luminosity of the planet and use it to model giant planets on 10 au circular and eccentric orbits around a solar mass star. We find that this feedback reduces but does not halt the accretion on to the planet, although this result might depend on the near-coincident radial ranges where both recipes are implemented. Our simulations also show that the planet heating gives the accretion rate a stochastic variability with an amplitude $\sim10\%$. A planet on an eccentric orbit ($e = 0.1$) presents a similar variability amplitude, but concentrated on a well-defined periodicity of half the orbital period and weaker broad-band noise, potentially allowing observations to discriminate between both cases. Finally, we find that the heating of the co-orbital region by the planet feedback alters the gas dynamics, reducing the difference between its orbital velocity and the Keplerian motion at the edge of the gap, which can have important consequences for the formation of dust rings.
#183 |
Three-Dimensional Modeling of Supersonic Gas Accretion and Ionized Envelope Dynamics in Jupiter-like Planets
Matias Montesinos
1
;
Juan Garrido-Deutelmoser
2
;
Nicolas Cuello
3
;
Jorge Cuadra
4
;
Amelia Ballo
5
;
Johan Olofsson
6
;
Matthias Schreiber
7
;
Mario Sucerquia
8
;
María Paula Ronco
9
;
Octavio Guilera
9
1 - Escuela de Ciencias, Universidad Viña del Mar.
2 - Instituto de Astrofísica, Pontificia Universidad Católica de Chile,.
3 - Univ. Grenoble Alpes, CNRS, IPAG,.
4 - Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez.
5 - European Southern Observatory.
6 - Max Planck Institute for Astronomy.
7 - Departamento de Física, Universidad Técnica Federico Santa María.
8 - Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso.
9 - Instituto de Astrofísica de La Plata.
Resumen:
We examine the essential dynamics and thermodynamics underlying gas giant accretion processes. By using high-performance three-dimensional hydrodynamical simulations, we model a Jupiter-mass planet embedded within a viscous gaseous disk. Our methodology incorporates a non-isothermal energy equation, enabling accurate computation of gas and radiative energy diffusion. We further introduce a radiative feedback term, which encapsulates the intrinsic luminosity of the planet, in our computational framework.
Our findings reveal the formation of an ionized envelope due to supersonic gas falling towards the planet, extending from 0.2 to 0.5 Hill radii near the planet. This envelope's radius, termed the 'ionization radius', demarcates a transition zone from pre-shock to shock regions, effectively establishing an accretion radius coinciding with the stopping radius. Notably, the stopping radius dictates the envelope's geometrical attributes.
The study underscores a robust linear relationship between the planet's accretion rate and the shock luminosity emanating from this region, with conditions propitious for H alpha emission present within the envelope. H alpha emission is an important accretion tracer to detect forming planets; however, the physical conditions near the planet remain controversial.
Importantly, our simulations show that the planet's radiative feedback reduces the velocity of the falling gas at higher altitudes ($\sim R_{\rm Hill}$), while simultaneously increasing the accretion rate within the ionization radius. This interaction promotes a 'fallback rate' towards the planet, culminating in enhanced shock luminosity. This research contributes to a better understanding of gas giant accretion's fundamental thermodynamic and dynamical properties, thereby carrying significant implications for detecting forming planets.
#210 |
Resonant Dynamics of Small Satellites and Particles in the Inner Saturnian System
Nelson Callegari Júnior
1
1 - Instituto de Geocências e Ciências Exatas - Unesp.
Resumen:
The Cassini-Huygens spacecraft took images of the last discovered Saturnian close-in small satellites. Having mean diameters d < 8 km and located in the regions of the ring system, they are Daphins (d=7.8 km), Pallene (d=4.4 km), Methone (d=3.2 km), Anthe (d=1.8 km), Aegaeon (d=0.7 km), S/2009 S 1 (d=0.3 km). The orbits of these small moons suffer complex gravitational perturbations of the non-central field of Saturn and the mid-sized satellites like Mimas. Some of these disturbances are resonant ones and contribute to their orbits' long-term stability. Additionally, all of them are involved gravitationally with the main rings, ring arcs, or diffuse rings.
In this talk, we first review the last results in the literature on the orbital dynamics of these small bodies with emphasis on mean-motion resonances and secular perturbations. Next, we show how the resonances play a role in the satellites' survival in long-term time scales of million years. Finally, we apply all these results critically discussing the evolution of the satellites and their rings counterparts after their formation.
#429 |
In search of the “Missing Mass”: Measuring Protoplanetary Disk Dust Masses with ALMA
Luisa Zamudio
1
;
Catherine Espaillat
2
;
Álvaro Ribas
3
;
Enrique Macias
4
;
Jesús Hernández
5
1 - Boston University.
2 - Institute for Astrophysical Research, Boston University.
3 - Institute of Astronomy, University of Cambridge.
4 - European Southern Observatory.
5 - Instituto de Astronomía, Universidad Nacional Autónoma de México.
Resumen:
Protoplanetary disks are an essential component of the planet formation process. The number and size of planets in a system are directly constrained by the amount of dust and gas in the disk. We present disk dust masses measured using spectral energy distribution (SED) modeling of ~50 disks around T Tauri stars (TTS) in the Serpens star-forming region, including ALMA 1.33mm fluxes from the literature. The disk masses that we calculate are a factor of ~2 higher than those reported in the literature. We find that this is because most works assume that the disk is optically thin at all mm wavelengths whereas our modeling finds that disks may be partially optically thick at mm wavelengths. Our results show that disks around TTS may have enough material to form planetary systems and could help alleviate the "missing" mass problem where there has been a reported discrepancy between the available mass in protoplanetary disks and the observable mass in observed exoplanet systems.
FOYER
Poster Group I - DISPLAY
19:30 - 20:30
Conferencia Divulgativa
Sede: Planetario de Montevideo. Dra. Verónica Motta: “Telescopios cósmicos: ¿qué sabemos sobre nuestro universo?”
SALÓN ROJO (150)
10:20 - 11:00
COFFEE BREAK
11:00 - 12:30
J: Galaxies and Cosmology
Galaxy Surveys
Chair: Camilo Delgado
#226 |
Automatic galaxy detection and measurement in large astronomical photometric surveys
Rodrigo Facundo Haack
1
;
Analía Viviana Smith Castelli
1
;
Claudia Mendes de Oliveira
2
;
Amanda Lopes
1
;
Felipe Almeida Fernandes
3
;
Laerte Sodré Jr.
2
1 - Instituto de Astrofísica de La Plata (CONICET-UNLP).
2 - Instituto de Astronomia, Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo.
3 - NSF’s NOIRLab, USA.
Resumen:
In this talk I will present the results of my Diploma Thesis and the first steps of my PhD work. Our goal was to detect, in the Southern Photometric Local Universe Survey (S-PLUS) images, galaxies previously reported in the literature as spectroscopically confirmed or probable members of the Fornax Cluster that do not appear or appear excessively deblended in the S-PLUS DR3 and iDR4 catalogs. This happens because the SExtractor input parameters used to obtain the published catalogs are intended to provide useful data for both galactic and extragalactic purposes.
As a main result we obtained catalogs with homogeneous photometry in the direction of the Fornax Cluster. For this purpose we found two sets of parameters suitable to automatically detect and measure different types of astronomical objects: on one hand, faint and/or compact objects close to bright galaxies and, on the other hand, bright and very extended objects. We were able to develop a pipeline that allows us to automate the entire process, works well in other surveys and is ready to be distributed publicly. These catalogs are being used to select targets to observe in the Fornax Cluster region in the framework of the CHANCES project of the 4MOST collaboration.
In the first steps of my PhD work we found that the SExtractor parameters found also work for other directions and distances, for example in the Hydra and Antlia Clusters. Two new sets of parameters were also identified: one capable of avoiding excessive splitting in star-forming galaxies and another that allows us to recover photometry of globular clusters and star-forming knots. We have also applied regression techniques with Machine Learning to solve the problem of missing data (lack of information in some filter) in the catalogs, and from this, perform template-fitting for each of the sources using LEPHARE.
#167 |
The 4MOST spectroscopic survey facility and the CHileAN Cluster galaxy Evolution Survey (CHANCES)
Christopher Haines
1
1 - Universidad de Atacama.
Resumen:
4MOST is ESO’s flagship spectroscopic survey facility that will be installed on the 4m VISTA telescope at Cerro Paranal next year. It is a fibre-fed spectrograph able to simultaneously obtain high-resolution spectra for 2400 objects over a field of view of 4.2 square degrees. It will carry out 18 public spectroscopic surveys that are expected to deliver spectra for 25 million objects across the entire Southern hemisphere over the first 5 years of operations from October 2024. We present the CHileAN Cluster galaxy Evolution Survey (CHANCES), one of the public surveys to be carried out with 4MOST. CHANCES will target 300,000 galaxies in and around 150 of the most massive galaxy clusters in the local Universe and out to z=0.45. We will target galaxies out to 5r200 from each cluster, enabling us to map the surrounding filamentary large-scale structures and identify the infalling X-ray groups that mark the key sites for pre-processing of galaxies prior to their arrival into the clusters. A second science focus will be the evolution of the cluster dwarf population in nearby clusters where we will push to stellar masses of 10$^9$ M$_{\odot}$ and below. Such low-mass galaxies outside of clusters are naturally gas-rich and will form the bulk of detections in ongoing and upcoming HI surveys from MeerKAT, ASKAP and SKA. The impact of cluster and group environments on the HI gas contents of low-mass galaxies is a key science objective of these HI surveys and should provide natural synergies with CHANCES.
#440 |
The Next Generation Fornax Survey (NGFS)
Thomas H. Puzia
1
;
Yasna Ordenes-Briceño
1
;
Paul Eigenthaler
1
;
Matías Blaña
1
;
Bryan Miller
2
;
Prasanta Nayak
1
;
Rohan Rahatgaonkar
1
;
Tuila Ziliotto
3
;
Mareclo Mora
4
;
Alejandra Hernandez
5
;
Evelyn Johnston
6
1 - Pontificia Universidad Católica de Chile.
2 - Gemini Obseratory/NSF’s NOIRLab.
3 - Università degli studi di Padova.
4 - Las Campanas Observatory.
5 - Universidad de Atacama.
6 - Universidad Diego Portales.
Resumen:
The Next Generation Fornax Survey (NGFS) targets all baryonic structures down to GC masses within the virial sphere of the Fornax galaxy cluster, utilizing the optical bands $u', g'$, and $i'$ in conjunction with the near-infrared (NIR) $J$ and $K_s$ filters. The NGFS uses an intricate observing technique to reach deep surface brightness limits that allows us to detect ultra-low surface brightness dwarf galaxies. Using the observing efficiency of DECam on the Blanco telescope at CTIO, complemented by NIR observations from VIRCAM on the VISTA telescope at ESO, we have secured large enough samples of galaxies to conduct volume-limited studies of their scaling relations. In this talk, I will present exciting new results based on the H-alpha extension of NGFS, showing intriguing recent star-formation activity in galaxies. Furthermore, I will showcase our most recent findings related to the dynamical properties of satellite galaxies within the Fornax galaxy cluster. Our analysis has identified a distinct transition radius, demarcating two zones where satellites exhibit varying properties of tidal stress. Intriguingly, this substructure mirrors patterns observed in cosmological galaxy simulations. Furthermore, when examining diverse cosmic environments, we discern a comparable transition radius in the Virgo galaxy cluster, as well as among the satellite galaxies of both the Milky Way and Andromeda. Finally, I will also discuss NGFS in the context with our other ongoing projects such as the Neighborhood Watch survey, which targets lower-density environments in the local universe.
#563 |
Morphological characterization of the MaNGA galaxies
Jose Antonio Vazquez-Mata
1
;
Hector Hernandez
1
;
Vladimir Avila
1
;
Aldo Rodriguez
1
;
Ivan Lacerna
2
1 - UNAM.
2 - Universidad de Atacama.
Resumen:
Galaxy morphology summarises the internal and external physical processes that lead to the present shapes of galaxies. A reliable morphological classification is therefore essential for analysing and interpreting the physical properties of galaxies.
In this presentation, I will discuss the recent Visual Morphology Catalogue (a SDSS-VAC) for the whole MaNGA galaxies. This catalogue introduces an innovative method for morphologically classifying galaxies across the complete Hubble sequence with high accuracy. It enables us to identify not only bars, but also faint tidal streams surrounding galaxies. We also estimated the structural parameters, concentration, asymmetry and clumpiness. This classification, identification and estimation is based on deep images from the DESI Legacy Surveys, coupled with meticulous image processing techniques.
We have correlated these findings with galaxy properties such as stellar mass, colours and stellar populations age. This has revealed distinct correlations between bars, tidal streams, and both morphology and stellar mass. Through the galaxy stellar mass function, we have investigated the contribution of each individual morphological type within specific stellar mass ranges. This exploration has unveiled the contribution by each type across different mass thresholds. For instance, Elliptical galaxies exclusively dominate the high mass end, with a non- influence extending to stellar masses below $logM_{\ast}$=10. Conversely, very late galaxies govern the low mass domain. Finally we present results that establish comprehensive connections between all reliably morphological types and the group environmental context (galaxies are divided into central or satellites).
#344 |
Characterizing Halpha emission in the Fornax cluster with S-PLUS
Amanda Lopes
1
;
Analía Smith-Castelli
1
;
Eduardo Telles
2
1 - Instituto de Astrofísica de La Plata.
2 - Observatório Nacional (ON/MCTI).
Resumen:
Emission lines in galaxies are a valuable source of information, allowing the study of star formation activity, the identification of active galactic nuclei, among others. The filter configuration of S-PLUS (Southern Photometric Local Universe Survey) is ideal to detect emission by its combination of 7 narrow and 5 broad optical passband filters. An interesting topic to investigate is the characteristics of the emitters in high density environments. Do they present a specific location within the cluster? How is the relation between the emission morphology and the galaxy morphology? The answer to such questions can give us clues about the formation of a given cluster. In this context, the Fornax cluster is a great target to be analyzed, as the Halpha+[NII] emission lines are located within the J0660 band of S-PLUS, and its proximity provides large enough galaxies to study their emission spatial distribution. In this talk we will present our code (P.E.L.E., Pixel-to-pixel Emission Line Estimate) to create Halpha+[NII] maps based on the three filter method applied to S-PLUS images, and our main results derived for 213 Fornax galaxy members, including the spatial distribution and the phase-space diagram of Halpha emitters, the relation between Halpha emission and the galaxy Sersic index, and the comparison between P.E.L.E. maps and the results from Fornax 3D project.
#025 |
The VVV near-IR galaxy catalogue in a Northern part of the Galactic disc
Ingrid Vanessa Daza Perilla
1
;
Mario Sgró
1
;
Laura Baravalle
1
;
María Alonso
1
;
Carolina Villalon
1
;
Marcelo Lares
1
;
Mario Soto
1
;
Jose Nilo
2
;
Carlos Valotto
1
;
Pamela Cortés
2
;
Dante Minniti
3
;
Maren Hempel
4
1 - Instituto de Astronomía Teórica y Experimental.
2 - Facultad de Ciencias, Physics and astronomy.
3 - Departamento de Fisica, Universidade Federal de Santa Catarina.
4 - Instituto de Astrofisica - Facultad de Ciencias Exactas - Universidad Andres Bello.
Resumen:
The automated identification of extragalactic objects in large photometric surveys provides reliable and reproducible samples of galaxies in less time than procedures involving human interaction. This problem, however, is more challenging in regions near the Galactic disc where the extinction by dust is greater. We present the methodology for the automatic classification of galaxies and non-galaxies at low Galactic latitude regions using both images and, photometric and morphological near-IR data from the VVVX survey. Using the VVV NIRGC, we analyse by classical and unsupervised statistical methods the most relevant features for galaxy identification. This catalogue was also used to generate datasets of extragalatic candidates from a pipeline and train a Convolutional Neural Network with image data and an Extreme Gradient Boosting architecture with photometric and morphological data.
This allows us to derive probability catalogues used to analyse the completeness and purity as a function of the configuration parameters and to explore the best combinations of the models. The resulting classifier reaches an F1-score of 0.67, a purity of 65 per cent and a completeness of 69 per cent.
As a test case, we apply this methodology to the VVVX survey in part of the Northern disc region, generating a dataset of 172,396 extragalatic candidates with probabilities of being galaxies. In addition, we present the VVV NIR Galaxy Catalogue.
12:30 - 14:30
LUNCH
16:20 - 17:00
COFFEE BREAK
17:00 - 18:15
J: Galaxies and Cosmology
Gravitational lensing
Chair: Eduardo Cypriano
#228 |
Cosmological applications of newly discovered gravitational lensed quasars
Verónica Motta
1
1 - Universidad de Valparaíso.
Resumen:
Strong lensing is a useful technique for examining astrophysical issues such as the general content and kinematics of the Universe as well as the study of distant active galactic nuclei (AGN) that are too small to be resolved with current telescopes. As variable sources, AGNs enable measurements of the time delays between images, which can be used to measure absolute distances (i.e., an alternative technique to constrain the Hubble constant). Microlensing (the brightness variations caused by stars as they move in front of each quasar image) of the compact source can be used to probe the mass at compact scales in the lens galaxy (Initial Mass Function) as well as the innermost structure of the source (accretion disk structure).
AGNs are often lensed into two images; four images (quads) are less frequent. For cosmology studies, such as measuring the distance to objects, quads are preferable because their modeling is more precise. In contrast to the 15 previously known quads, in recent years our collaboration has discovered 30 additional quads for which I will present some results of those astrophysical applications.
#093 |
Parametric Strong-Lensing Analysis of a High-Disturbance Galaxy Cluster
Carla Cornil-Baïotto
1
1 - Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Avda. Gran Bretaña 1111, Valparaíso, Chile.
Resumen:
Galaxy clusters, as the largest gravitationally bound systems in the Universe, are an important laboratory for studying dark matter. In the inner core of rich galaxy clusters, gravity can create remarkable visual mirages through the significant bending of light by high mass concentrations, the so-called strong gravitational lensing phenomenon. Strong lens modeling plays a key role in mapping the mass distribution of galaxy clusters, providing insights into the spatial distribution of dark matter and its role in cluster evolution. In this short talk, I will present the results of the parametric strong lensing analysis of a highly disturbed galaxy cluster. Firstly, I will detail the approach to model the mass distribution of its core that hosts a giant arc and multiple images of distant galaxies in the optical, using the software Lenstool. Then, I will introduce the cluster’s multi-wavelength analysis, taking advantage of HST, DES, MUSE, MeerKAT, and XMM-Newton observations. This extensive multi-wavelength analysis allowed us to understand the effects of the environment turbulence on the high ellipticity of the cluster’s central dark matter halo, and recover the tumultuous evolutionary history of this galaxy cluster (Cornil-Baïotto et al., in prep).
#191 |
Microlensing scale estimation for 190 lensed quasars
Felipe Avila Vera
1
;
Verónica Motta
1
1 - Universidad de Valparaíso.
Resumen:
Gravitationally lensed quasars (QSO) have multiple applications in cosmology and to study the structure of the quasar. One of the problems for the modeling is that the image fluxes could be affected by microlensing produced by stars in the lens galaxy. Recently, TDCosmo has almost doubled the known systems with respect to the previous decade. We present, for the first time, the automatic modeling of 190 systems to obtain a homogeneous sample, and reduce systematic errors in lens parameters. These models are used to estimate the microlensing timescales, i.e. the timescale in which the source (QSO) crosses the Einstein radius of the microlens (star), which also introduces variation in the QSO image fluxes. We found median Einstein radius crossing time scales of 22.17 years, and median source crossing time scale of 8.5 months. This means that in $\sim$ 10 years, part of the sources will be on the caustics (affected by microlensing), and the other part will be quiescent
#104 |
Uniform modeling of 21 strong lensing systems in ground-based surveys: Follow-up observations and constraints on modified gravity
João Paulo Correia de França
1
;
Martin Makler
2
;
Renan Oliveira
3
;
James Nightingale
4
;
Ingrid Beloto
5
;
Eduardo Cypriano
5
1 - CBPF.
2 - CBPF, ICAS, ICIF, UNSAM.
3 - UFES.
4 - Durham University.
5 - IAG USP.
Resumen:
Gravitational arcs are strongly magnified images of distant galaxies (known as sources) caused by the deflection of light produced by a foreground galaxy or galaxy cluster (the lens). The modeling of gravitational lenses has been used to study high-redshift sources, to assess the mass distribution in the lens, to constrain cosmological parameters and to set limits on modified gravity. In particular, with the next generation wide-field imaging surveys, such as Euclid and Rubin (LSST), we expect to discover on the order of $10^4$ such systems, which will require efficient and automated modeling methods to explore their applications. In this work, we present a (semi-)automated modeling pipeline which iteratively derives the PSF from the images, masks nearby non-lensed sources and simultaneously derives the lens model parameters and the source light in a non-regular Voronoi grid in multiwavelength data. With this pipeline we were able to model uniformly a sample of 21 gravitational lenses in ground-based surveys including the Hyper Suprime Cam (HSC) SuGOHI sample, the Dark Energy Survey (DES), the Kilo-Degree Survey (KiDS) and the Legacy Survey. Additionally, we carried out spectroscopic follow-up observations on the SOuthern Astrophysical Research (SOAR) telescope specially aiming to measure the lens velocity dispersions. We combine the results from the SOAR data with our lens modeling to derive constraints on the post-Newtonian parameter $\eta_{PPN}$. There are the first constraints on $\eta_{PPN}$ purely from ground-based data and with a totally independent sample from other studies in the literature. These results pave the way to study the constraints on $\eta_{PPN}$ that could be derived from LSST data.
#582 |
Accretion disk parameters estimations in The Einstein Cross using X-shooter (VLT) spectra and multiple epochs photometry data.
Ramses Jerez-Nicurcar
1
;
Veronica Motta
1
1 - Universidad de Valparaiso.
Resumen:
Until today, there have been nearly 220 gravitational lens systems discovered and confirmed with different methods and techniques, and only a fraction of them have been able to estimate the size of their internal structure (i.e., accretion disk, broad emission line region).
In my Master’s thesis we studied the gravitationallens systems QSO2237+0305 (The Einstein’s Cross) which show four quasar images. This lens system is peculiar because the lensing galaxy is very close ( zl = 0.04 and Zs=1.69).
We examined the emission lines and the continuum emission below them using the spectra of each lensed image and also questioned the existence of extinction in the core of the emission lines.
We confirmed the existence of microlensing effect in the continuum spectra of the quasar images and also with the photometric observation. Besides, we have observed a wavelength dependency in this effect, which means in the detection of the chromatic microlensing effect. This enables us to model the accretion disk with a temperature profile p and a size r, with a power law relating the two parameters: r $\propto$ $\lambda^{p}$. Our measurements of the accretion disk parameters were compared with the previous estimations in the literature, which are in good agreement.
SALÓN DORADO (120)
10:20 - 11:00
COFFEE BREAK
11:00 - 12:30
H: ISM and Local Universe
ISM, Milky Way
Chair: Luis Aguilar
#073 |
The MUSE view on the Sculptor: a detailed study of the ionized interstellar medium in NGC 253
Resumen:
Galaxy evolution and star formation are tightly intertwined. However, star formation is a local process, acting on single H II regions and molecular clouds ($\sim$ 10 pc); how it can have affect galactic properties on kcp scales and drive their evolution is still one of the key open questions in astronomy. Multiwavelength observations of galaxies that can resolve the key actors in the star formation process (e.g. molecular clouds, star-forming regions, young clusters) while keeping the view of galaxies as a whole are key to understand the interplay between such small scale process and its large scale effects.
In this talk, I will present a new MUSE survey of the closest starburst galaxy to the Milky Way: NGC 253. The survey covers a total area of 20$\times$5 arcmin$^2$ (20$\times$5 kpc$^2$ at the distance of the galaxy, 3.5 Mpc) at a resolution of $\sim$15 pc, giving us a detailed view of the galactic interstellar medium that is only second to what is possible in the Milky Way and a handful of other extremely nearby objects. At the same time, the external point of view allowed us to cover the entire extension of the star-forming disk. Preliminary results show that the mosaic, which is the largest contiguous mosaic ever observed by MUSE so far, includes $\sim$6500 ionized nebulae that will be instrumental to investigate topics, among others, like the ionization and temperature structure of HII regions, the small and large scale effects of stellar feedback, and the local and galactic scale matter cycle.
#478 |
Tracing Dark Matter Halo Wakes with Stellar Halos
Chervin Laporte
1
;
Nicolas Garavito-Camargo
2
;
João Amarante
1
1 - University of Barcelona.
2 - Flatiron Institute CCA.
Resumen:
The recent infall of the Large Magellanic Cloud (LMC) onto the Milky Way provides us a unique opportunity to observe dynamical friction in action and trace large scale dark matter halo (DM) distortions in the Galaxy through observations of the stellar halo. The DM halo wake induced by the LMC's infall is thought to extend between 50 kpc all the way to the virial radius, a region still poorly explored due to the paucity of tracers at large distances. Currently, all predictions of the Milky Way's DM halo wake have relied on the poor/simplifying assumption of a smooth stellar halo, which is clearly broken beyond 30 kpc where the stellar halo is primarily constituted of substructure and non-phase mixed stellar debris. Any hope of detecting the global DM halo wake of the MW thus relies on a careful identification of known stellar debris beyond 50 kpc and models taking into account the non-smooth nature of galactic stellar halos. In this contribution, I present the first predictions of the response of a statistical sample of Galactic stellar halos formed through hierarchical accretions reacting to the DM halo wake induced by the LMC on a first infall. I will present full-sky maps in kinematic, density space of the stellar halo in the presence/absence of the LMC and how these can be used to probe large-scale DM halo distortions. Furthermore, I will show that the LMC induces remarkably pronounced isophotal twisting of the entire Galactic stellar halo in the orbital plane of the LMC, tracing the global DM halo wake, a signature awaiting detection with LSST and EUCLID. Finally, I will present a recent fully probabilistic analysis of the stellar halo using BHBs in DECaLS which successfully discerns the local wake behind the LMC but with no conclusive signs of a global wake.
#276 |
Keeping track of nearly a hundred stellar streams in the Milky Way: the galstreams library
Cecilia Mateu
1
1 - Facultad de Ciencias, Universidad de la República, Uruguay.
Resumen:
Stellar streams play in dynamics a similar role as stellar clusters do in stellar evolution: they are relatively simple systems of stars whose common properties allow rewinding evolutionary or dynamical processes much harder to disentangle in the Galactic field. Formed as stars are stripped from a dwarf galaxy or globular cluster by the Milky Way’s tidal forces, stellar streams are fossil records of accretion that are best preserved in the halo, where streams are long lived. Unearthing this record is essential to reconstructing the Galaxy’s accretion history, and modeling its dynamics is key to constrain the distribution of dark matter at the scales of the Galaxy and its satellites. In this contribution I will showcase the latest version of the galstreams library, a compilation that collates information scattered across the literature for nearly a hundred stellar streams known in the Milky Way, and use it to provide an ensemble view of the Galactic system of stellar streams’s properties, its current observational biases, and results inspired by recent discoveries made possible by the Gaia mission.
#346 |
Systematic census of RR Lyrae in cluster vs. tails of stellar streams with an associated cluster
Bruno Domínguez
1
;
Cecilia Mateu
1
;
Pau Ramos
2
1 - Universidad de la República.
2 - National Astronomical Observatory of Japan.
Resumen:
Currently it is known that galaxies like ours have formed gradually, progressively assimilating smaller galaxies. These accretion events have left fossil records that can be discovered by studying the most ancient populations such as the Galactic halo.\\
An important part of this fossil record are the globular clusters and stellar streams present in the halo. Studies have revealed that a large number of globular clusters fell into the Milky Way along with their respective host galaxies. But, these are only the “surviving” clusters. During the accretion process, clusters and dwarf galaxies can be disrupted in the halo thanks to tidal forces, generating stellar streams. Almost one hundred streams are known in the Galaxy today, most of them produced by globular clusters.\\
Our general aim is to search for RR Lyrae associated to all known stellar streams. The RR Lyrae are horizontal branch pulsating stars known for being standard candles, in this way we can obtain precise distances of the stars being able to determine the distance gradient of the stellar stream. This will be needed to determine its dynamic properties.\\
In a first exploration for the Pal5 stellar stream 10 RR Lyrae were found in the cluster and 17 in the tails; in the M68-Fjorm stream the opposite is found, while there are over 40 RR Lyrae in the cluster, only less than a handful are found in the tails. Furthermore, in the case of Pal5 the RR Lyrae are segregated: The majority of the RRc (8/12) are in the cluster while the majority of the RRab (13/15) are in the tails. In this talk we will present the first results of a systematic census of RR Lyrae in the cluster vs. the tails of the streams with an associated cluster.
#452 |
Red Clump stars and reddening law towards the Nuclear Bulge of the Milky Way
Álvaro Valenzuela Navarro
1
;
Manuela Zoccali
1
;
Elena Valenti
2
;
Rodrigo Contreras Ramos
1
;
Carme Gallart
3
;
Claudio Salvo
4
;
Julio Olivares Carvajal
1
1 - Pontificia Universidad Católica de Chile / Instituto Milenio de Astrofísica.
2 - European Southern Observatory.
3 - Instituto de Astrofísica de Canarias / Universidad de La Laguna.
4 - Pontificia Universidad Católica de Chile.
Resumen:
The Nuclear Bulge is a unique region of the Milky Way, located in the innermost ~220 pc of our Galaxy. Here, both gas structures -i.e. Central Molecular Zone, CMZ- and stellar components -i.e. Nuclear Stellar Disc, NSD- coexist. While the CMZ has been extensively studied in radio/sub-mm, the NSD lacks comprehensive observational studies. This is due to a combination of severe extinction and crowding when observing stars. In this context, Red Clump stars (RC) studies in near infrared (NIR) are the ideal structure tracers. In this talk, I will review the importance of the Nuclear Bulge for the entire Galaxy, and present the HAWK-I@VLT deep NIR high-quality photometry study of RC stars. Given the degeneracy of distance and extinction, we employ the shape of the RC to constrain the line-of-sight (LOS) distribution and the extinction law simultaneously. We obtained a set of feasible extinction laws in this particular region, along with different LOS distributions of RC stars. These results are key for further computation of the star formation history of the Nuclear Bulge, and to improve our understanding of the interaction of all structures lying here.
#480 |
An experiment in near field cosmology: Characterization of the stellar counterpart of the Magellanic wake
Manuel Cavieres
1
;
Julio Chaname
1
1 - Pontificia Universidad Catolica de Chile.
Resumen:
Gravitational interactions between the Large Magellanic Cloud (LMC) and the outer halo of the Milky Way are expected to generate a large-scale asymmetry that spans the northern Galactic hemisphere (collective response), along with a localized wake that trails the LMC's orbit. These predicted phenomena present opportunities to gain insights into the Milky Way's mass and the distribution of dark matter within its outer halo. A previous study using Gaia Early Data Release 3 and WISE surveys reported the detection of both the collective response and the wake. However, the low number statistics of the wake detection hampered an in-depth characterization of the densities involved.
In our study, we leverage deep near-infrared and optical photometry from the VISTA and DECam instruments allowing for a clean sample of halo stars that reach the oldest main sequence turnoffs at 100 kpc. Preliminary results using near-main sequence turn-off photometric distances show that the Magellanic Wake is present in our data with enough stars in the outer halo (~ 600 sources further than 60 kpc) for the detection to be considered statistically significant. This research provides us with the required data to characterize the density and position of the wake which will provide a point of comparison and constraints to simulations.
12:30 - 14:30
LUNCH
16:20 - 17:00
COFFEE BREAK
17:00 - 18:00
H: ISM and Local Universe
Milky Way
Chair: Dante Minnitti
#354 |
Where are the super metal-rich Bulge globular clusters? Revealing an inconsistency
Elisa Rita Garro
1
;
Dante Minniti
2
;
José Fernández-Trincado
3
1 - ESO.
2 - UNAB.
3 - UCN.
Resumen:
Many globular clusters (GCs) in the Milky Way (MW) have been studied in recent years, especially in hidden regions, like the MW bulge. We want to understand what we can learn if we include these new objects into the MWGC system that we know today. We catalogue 45 recently discovered GCs.
We use metallicity distribution (MD), luminosity function (LF), age distribution, and [Mg/Fe]-[Fe/H] diagram for investigating the Galactic bulge GC system. We consider 3 samples: new GCs, known and well-characterized GCs and a merging of these two samples.
We find a double-peaked distribution for the LF and MDs. We also construct the MD for the field star sample, and comparing this with that one of the GCs, we learn that a high percentage of field stars show [Fe/H]>0, whereas we do not detect any GCs in the same metallicity range. Therefore, we construct the age-metallicity diagram for both samples, noting that the old and metal-poor population is represented by GCs, while the young and metal-rich population corresponds to field stars. We build up the [Mg/Fe]-[Fe/H] diagram for known GCs and field stars, finding that the GCs are formed during the initial burst. The most metal-rich GCs seem to be the outcome of a violent and bursty star formation in the bulge or from an accreted metal-rich elliptical galaxy.
We conclude that the bimodal distribution of GCLF suggests that many GCs have been accreted during past merging events. This is also supported by the MD, which indicates that the metal-poor component is mainly the contribution due to the tidal disruption of dwarf-like objects whereas the metal-rich population is related to the formation of the bulge and/or disk. The difference that we notice between the cluster and field star samples should be sought in the evolutionary difference between these two stellar populations.
#084 |
Structure, kinematics and time evolution of the Galactic Warp revealed by
Classical Cepheids
Mauro Cabrera
1
;
Cecilia Mateu
1
;
Pau Ramos
2
;
Mercè Romero-Gómez
3
;
Teresa Antoja
3
;
Luis Aguilar
4
1 - Departamento de Astronomía, Instituto de Física, Universidad de la República, Iguá 4225, CP 11400 Montevideo, Uruguay.
2 - National Astronomical Observatory of Japan, Mitaka-shi, Tokyo 181-8588, Japan.
3 - Institut de Ciències del Cosmos, Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, E-08028 Barcelona, Spain.
4 - Instituto de Astronomía, Universidad Nacional Autonóma de México, Apdo. Postal 877, Ensenada, 22800 Baja California, Mexico.
Resumen:
The warp is a well-known undulation of the Milky Way disc. Its structure has been widely studied, but only since Gaia DR2 has it been possible to reveal its kinematic signature beyond the solar neighbourhood. In this work we will present an analysis of the warp's structure by means of a Fourier decomposition in vertical high ($Z$) and vertical velocity ($V_z$) traced by Cepheids. We find a clear but complex signal that in both variables reveals an asymmetrical warp. In $Z$ we find the warp to be almost symmetric in amplitude at the disc's outskirts but with the two extremes never being diametrically opposed at any radius and the line of nodes presenting a twist in the direction of stellar rotation for $R>11$ kpc. In $V_z$ an $m=2$ mode is needed to represent the kinematic signal of the warp, reflecting its azimuthal asymmetry. We also find that the line of maximum vertical velocity is similarly twisted but does not overlap with the line of nodes, it trails behind by $\approx 25$ deg. We will show how the twisted line of maximum $V_z$ creates "arches" in the mean $V_z$ as a function of radii, a signature of global warp kinematics that has been observed with other tracers with less azimuthal coverage of the disc. Finally, a joint analysis of the Fourier decompositions in $Z$ and $V_z$ allows us to develop a new model-independent formalism to derive the pattern speed and change in amplitude of each mode at each radii. By applying it to our results for the Cepheids we find, for the $m=1$ mode, a constant pattern speed in the direction of stellar rotation of $9.18$ km/s/kpc, a constant amplitude up to $R\approx 14$ kpc and a slight increase in amplitude at larger radii, in agreement with previous works.
#441 |
All-sky Kinematics and Chemistry of Monoceros Stellar Overdensity
Lais Borbolato
1
;
Hélio D. Perottoni
2
;
Silvia Rossi
1
;
Guilherme Limberg
1
;
Angeles Pérez-Villegas
3
;
Friedrich Anders
4
;
Teresa Antoja
4
;
Chervin F. P. Laporte
4
;
Helio J. Rocha-Pinto
5
;
Rafael M. Santucci
6
1 - Universidade de São Paulo.
2 - Polish Academy of Sciences.
3 - Universidad Nacional Autónoma de México.
4 - Universitat de Barcelona.
5 - Universidade Federal do Rio de Janeiro.
6 - Universidade Federal de Goiás.
Resumen:
We use a combination of data from 2MASS, WISE, APOGEE, and Gaia DR3 to study the kinematic and chemical properties of Monoceros' stellar overdensity. Monoceros is a structure located towards the Galactic anticenter and close to the Galactic plane. We identified that its stars have azimuthal velocity in the range of 200 < v(phi) (km/s) < 250. Combining their kinematics and spatial distribution, we designed a new method to select stars from this overdensity. This method allows us to easily identify the structure in both hemispheres and estimate their distances. Furthermore, we characterized, for the first time, the Monoceros overdensity in several chemical-abundance spaces. Our results demonstrate that the southern (Mon-S) and northern (Mon-N) regions of Monoceros exhibit indistinguishable chemical compositions, and we also confirm their resemblance to stars found in the thin disk of the Galaxy and suggesting an in situ formation.
18:00 - 18:30
G: Stars and Stellar Physics
Stellar Populations
Chair: Dante Minnitti
#321 |
The Metallicity Gradient of Sagittarius Dwarf Spheroidal Galaxy Prior to Infall Constrained by S-PLUS Observations of its Tidal Stream
Felipe Almeida-Fernandes
1
;
Guilherme Limberg
1
;
Helio Perottoni
2
;
Joao Amarante
3
;
Pierre Martho
1
;
Eduardo Pereira
4
;
Gabriel Fabiano de Souza
1
;
Guilherme Bolutavicius
1
;
Rafael Santucci
5
;
Silvia Rossi
1
;
Marcos Vinicius Cordeiro da Silva
4
;
Marcelo Borges
4
;
Vinicius Placco
6
;
Claudia Mendes de Oliveira
1
1 - Universidade de Sao Paulo.
2 - Nicolaus Copernicus Astronomical Center.
3 - Institut de Ciencies del Cosmos - Universitat de Barcelona.
4 - Observatorio Nacional.
5 - Universidade Federal de Goias.
6 - NOIRLAB.
Resumen:
Several major substructures, like the Sagittarius stream, have been observed in the Milky Way halo over the past few years. These substructures are likely remnants of past accretion events, therefore, investigating their origin and nature is crucial to understanding the formation and evolution of our Galaxy in the context of hierarchical galactic formation. In this study, we used photometric metallicities to study the current metallicity gradient in the arms of the Sagittarius stream, and compared these results to predictions of N-body simulations to reconstruct the original metallicity gradient in the Sagittarius dwarf galaxy prior to its accretion by the Milky Way. To build our sample, we did a cross-match between S-PLUS DR4 photometry and a list of Sagittarius stream members, available in the literature, which were selected using astrometric data from Gaia DR3. We applied two different techniques to estimate photometric metallicities: an artificial neural network and a random-forest algorithm, resulting in two samples of, respectively, 7398 and 4683 stars with reliable metallicity measurements. We measured a gradient of $\approx -0.0030$ dex/degree for the leading arm of the stream. For the trailing arm, we found no significant gradient when considering the whole area covered by S-PLUS ($20 \leq \Lambda \leq 130$ degrees), but the region near the core ($20 \leq \Lambda \leq 70$ degrees) also present a gradient of $\approx -0.0035$ dex/degree. We imprinted artificial metallicities to particles in a N-body simulation of the stream, available in the literature, considering different scenarios of original metallicity gradients. Comparing simulated and observed results, we were able to show that the current metallicity gradient in the stream is consistent with an original metallicity gradient between $-0.22$ and $-0.37$ dex/kpc in the Sagittarius progenitor galaxy.
#503 |
Unveiling Galactic Secrets: Chemical Tagging of Milky Way Variable Stars with SPLUS
Debasish Hazarika
1
;
Carlos E. Ferreira Lopes
1
1 - Institute of Astronomy and Planetary Sciences, University of Atacama, Chile.
Resumen:
We present the chemical tagging analysis of over 35,000 variables within the Milky Way, classified using the unique multiwavelength 12-bands photometric observational data from the ongoing Southern Photometric Local Universe Survey (S-PLUS). Leveraging the chemical and elemental information of individual stars as training set from spectroscopic surveys such as LAMOST and APOGEE, we utilize machine learning models to predict the chemical abundances ([Fe/H], [Alpha/H], [Ca/Fe], [C/Fe], [Mg/Fe], [Si/Fe], [Ni/Fe], [Na/Fe]) of individual stars in the S-PLUS based on their photometric colors. Additionally, the information on radial velocity and proper motion from RAVE \\& GAIA along with the predicted chemical abundances helps us accurately position the variables in the Milky Way and facilitate the separation of galactic components such as thin, thick disks, halo etc., based on multiple spatial aspects in the positional, chemical, and dynamical space, which is crucial for deriving new insights about the structure and kinematics of our galaxy.
#560 |
An internal view of Stellar system Terzan 5
Francesco Mauro
1
;
Vanessa Gotta
1
;
Christian Moni Bidin
1
;
Doug Geisler
2
;
Francesco Ferraro
3
1 - Instituto de Astronomia, Universidad catolica del Norte.
2 - Departamento de astronomia, Universidad La Serena.
3 - Department of Physics and Astronomy, University of Bologna.
Resumen:
We present the spacial-photometric analysis of the inner part of the interesting globular cluster Terzan 5 using observed with GeMS/GSAOI and HST. Terzan 5 is one of the most massive globular cluster of the Milky Way localized near the center of the Galactic bulge. It is characterized by a double horizontal branch, due to two stellar population that show a substantial difference in age and metallicity (~7Ga and 0.5 dex, respectively); for this reason Terzan 5 is thought to be one of few remaining building blocks of the Galactic Bulge, together with Liller1. In this work we analyze the populations of Terzan 5 determine their spatial distributions, the fundamental parameters of the stellar system.
