segunda-feira 27 de novembro
SALÓN AZUL
08:15 - 09:00
REGISTRATION
Conference registration
09:00 - 09:15
INAUGURATION
09:15 - 10:05
Plenary Review Talk
Invited Speaker:
Yara Jaffe
- Universidad Técnica Federico Santa María
(Chile)
[cv]
Yara Jaffe
Universidad Técnica Federico Santa María
Curriculum Vitae:
I am a faculty member at the Physics Department of Universidad Tecnica Federico Santa Maria in Valparaiso, Chile. I obtained my PhD at the University of Nottingham and held postdoctoral positions at INAF-Padova, Universidad de Concepción and ESO-Chile where I supported the VLT. My research focuses on understanding the effect of environment on the evolution of galaxies. I am part of the GASP collaboration dedicated to studying “jellyfish” galaxies, and I am co-PI of the upcoming CHANCES 4MOST Survey which will study over 300.000 galaxies in >100 massive clusters out to 5 virial radii in the last 4 Gyr of cosmic time.
Chair: Cecilia Mateu
#557 |
Galaxy evolution across the cosmic web
Yara Jaffé
1
1 - Universidad Técnica Federico Santa María.
Resumo:
From a galaxy's point of view, its environment has continued to evolve during its lifetime, going from lower to higher density regions as it moves across the cosmic web. I will review our current understanding of the effect of environment on galaxy evolution, including the consequences of gravitational interactions with other galaxies and hydrodynamical interactions with its host group or cluster. I will also show recent studies on galaxies caught in the act of transformation, such as the spectacular "jellyfish" galaxies which are in the process of gas stripping due to intense ram-pressure by the intracluster medium. I will further discuss the current challenges in our understanding of galaxy evolution, including the complexity imposed by the hierarchical formation of structure which leads galaxies to be "pre-processed" in groups and filaments prior entering a massive cluster. I will end with an overview of the ongoing and future observational prospectives in the field.
10:05 - 10:35
Plenary Target Talk
Invited Speaker:
Aldo Rodríguez-Puebla
- Instituto de Astronomía, UNAM
(México)
[cv]
Aldo Rodríguez-Puebla
Instituto de Astronomía, UNAM
Curriculum Vitae:
El Dr. Aldo Rodríguez-Puebla completó su Licenciatura en la Escuela Superior de Física y Matemáticas del Instituto Politécnico Nacional en México, seguida de una Maestría y Doctorado en el Instituto de Astronomía de la UNAM. Durante su tesis doctoral, recibió mención honorífica y la medalla Alfonso Caso a la mejor tesis en ciencias por su trabajo “La conexión galaxia-halo y su evolución”. Posteriormente, realizó una estancia postdoctoral de un año en la Universidad de Shanghai, Jiao Tong en China, y una estancia de dos años en la Universidad de California en Santa Cruz, Estados Unidos. Desde 2016, se unió al Instituto de Astronomía de la UNAM, donde actualmente se desempeña como investigador titular y es miembro del Sistema Nacional de Investigadores, nivel 2 en México. Aldo Rodríguez-Puebla estudia la formación y evolución de galaxias desde un contexto cosmológico al combinar simulaciones cosmológicas de N-cuerpos de materia oscura y observaciones de galaxias de catastros cosmológicos.
Chair: Cecilia Mateu
#229 |
The co-evolution between galaxies and dark matter halos
Aldo Rodriguez-Puebla
1
1 - Instituto de Astronomía, UNAM.
Resumo:
The current cosmological paradigm posits that dark matter halos provide the gravitational scaffolding for galaxy formation through a combination of hierarchical structure formation and non-linear local astrophysical processes. As a result, the growth and assembly history of dark matter halos are expected to influence the assembly history of galaxies which can leave observable imprints on their properties. This close and interdependent relationship between galaxies and halos is commonly referred to as the galaxy-halo connection. While the stellar mass of galaxies has been found to be strongly correlated with the mass of their dark matter halos, it is essential to note that the galaxy-halo connection is actually a multivariate distribution of galaxy and halo properties, which can be constrained using data from astronomical observations and simulations, the so-called semi-empirical modelling. In this talk, I discuss the semi-empirical model for the galaxy-halo connection. In particular, I will discuss EMPIRE which utilizes the assembly histories of dark matter halos and the multivariate distribution between galaxy and halo properties to infer the star formation histories of galaxies, galaxy sizes, as well as the accretion histories of their host supermassive black holes.
10:35 - 11:15
COFFEE BREAK
11:15 - 12:45
J: Galaxies and Cosmology
Galaxy formation and evolution
Chair: Mario Abadi
#404 |
The evolution of the intermediate to massive galaxy population: obscured and unobscured star formation, quenching and morphological transformation
Vladimir Avila-Reese
1
;
Aldo Rodriguez-Puebla
1
1 - Instituto de Astronomía, UNAM.
Resumo:
At high redshifts, when intermediate to massive galaxies were gas-rich and formed stars at high rates, most of them were probably in a regime of strong dust-obscured star formation (SF); they were dusty-star forming galaxies. How did these galaxies subsequently evolve as a function of mass and environment? Which galaxies underwent SF quenching and morphological transformation? And how did the dust-obscured SF fraction of those galaxies that remained as disk-dominated change with mass and time? We study these questions using EMPIRE, a sophisticated semi-empirical model for the evolution of the galaxy-halo connection within LCDM cosmology, and also using a statistical approach that combines the observed FUV and IR rest-frame luminosity functions with the galaxy stellar mass functions (GSMFs) at different redshifts. We find that 1) there is no inconsistency between the observed evolution of the FUV/IR LFs and the evolution of the SFR-$M_*$ relation and the GSMF of SF main sequence galaxies; 2) the dust-obscured SF fraction strongly increases with mass, while at $z\lesssim0.75$ massive galaxies become more transparent; and 3) the SF quenching is related to the increase in the inner stellar surface density. Finally, with our model we generate light cones in the sky and predict the number counts of submillimeter galaxies to compare with the results of deep FIR/submillimeter extragalactic surveys such as the forthcoming TolTEC-LMT survey.
#170 |
Galaxies in transformation: constraining the structural and stellar population parameters of galaxies undergoing ram-pressure stripping
GABRIEL AZEVEDO
1
1 - Universidade Federal do Rio Grande do Sul (UFRGS).
Resumo:
In dense regions like clusters, groups, and filaments, galaxies may experience a process called ram-pressure stripping (RPS). This occurs when the surrounding gas exerts pressure on the galaxy's interstellar material (ISM), causing it to be stripped away. The most extreme cases of RPS result in "jellyfish galaxies," where the stripped material forms asymmetric tentacle-like structures, giving rise to multiple star-forming regions.
RPS plays a crucial role in the theory of galaxy formation and evolution, as it is considered one of the main mechanisms leading to the suppression of star formation in galaxies within dense regions. This happens because RPS removes a significant portion of their gas reservoir. However, interestingly, jellyfish galaxies tend to exhibit higher star formation rates (SFR) compared to other star-forming galaxies in the same environments. This suggests that RPS actually triggers star formation in these galaxies.
In our study, we aim to identify potential jellyfish galaxies in the Deep fields of HSC (ELAIS-N1, COSMOS, XMM-LSS, and Deep2-3) using a combination of Hyper Supreme-CAM (HSC) photometry and Dark Energy Spectroscopic Instrument (DESI) spectrometry. The candidates are visually selected at a redshift of z~0.24, making use of the 5 broad band filters of HSC and the narrow band NB0816, which captures the $H\alpha$+[NII] lines. The $H\alpha$ emission is particularly useful for highlighting jellyfish features due to their high star formation activity. By employing specific combinations of HSC filters, we can better observe the morphology of these objects and also measure various properties such as colors, spectral emission-line fluxes, ionizing source diagrams, and spectral energy distribution (SED) fitting. In this presentation, we will present our methodology and show our first results for 4 clusters in the ELAIS-N1 field.
#199 |
Stellar population properties of massive compact galaxies at $z\sim0$: evidence of diversity in the formation pathways
Katia Slodkowski Clerici
1
;
Allan Schnorr Müller
1
;
Marina Trevisan
1
;
Tiago Vecchi Ricci
2
1 - Universidade Federal do Rio Grande do Sul.
2 - Universidade Federal da Fronteira Sul.
Resumo:
Galaxies can be classified according to their star formation activity as either star forming or quiescent. Star forming galaxies are rich in gas and vigorously form new stars. Quiescent galaxies have low star formation activity and old, metal-rich stellar populations. The quiescent galaxies observed at $z \sim 2-3$ are very different from their local counterparts. Particularly, they are extremely compact, with sizes a factor of $\sim 3-5$ smaller than quiescent galaxies at $z \sim 0$. Due to their small sizes and faint stellar continua spectroscopic studies of large samples are extremely challenging with current facilities. As an alternative, massive compact galaxies (MCGs) at low-redshifts can be explored as local analogues. We studied the stellar population properties of a large sample of $1858$ MCGs from the Sloan Digital Sky Survey. To assess if MCGs differ from typical quiescent galaxies in their stellar population properties, we build a control sample of average-sized quiescent (CSGs). Considering that the stellar population properties of quiescent galaxies correlate better with velocity dispersion ($\sigma_e$) than with parameters such as stellar mass, we compare MCGs and CSGs at fixed $\sigma_e$, finding that MCGs are older, have higher [$\alpha$/Fe] and lower metallicities, except for $\sigma_e \gtrsim 230$ km/s where MCGs and CSGs have similar ages. These differences are driven by variations in the stellar mass of galaxies at $\sigma_e$, CSGs are, on average, $ \sim 0.7$ dex more massive than MCGs of similar $\sigma_e$. We argue that the differences in stellar population properties and stellar mass point to MCGs and CSGs descending from different subgroups of the high-redshift quiescent population. Lastly, we found that the metallicity of MCGs shows a dependence on stellar mass at fixed $\sigma_e$, while the age and [$\alpha$/Fe] do not. We suggest that this is a possibly signature of different quenching pathways followed by MCGs.
#426 |
Reconstructing the Star Formation History in an Intermediate-Age Merger Remnant
Leandro Sesto
1
;
Carlos Escudero
1
;
Favio Faifer
1
1 - Instituto de Astrofísica La Plata (FCAGLP-CONICET).
Resumo:
Galaxy mergers are often mentioned in the literature as ideal places to study diverse starbursts triggered during fusion events. In that sense, the intermediate-age merger remnant NGC 1316, constitutes a perfect merger scenario to study complex large-scale star formation events in the Local Universe. This colossal galaxy, which dominates an important sub-group of the Fornax galaxy cluster, still shows the scars of its violent near past.
In a series of previous works, we confirmed the existence of a complex globular cluster system associated with NGC 1316. Using photometric and spectroscopic GEMINI/GMOS data, we found that the globular cluster system is dominated by the presence of an unusual young and metal-rich subpopulation. In addition, several objects in our sample seem to show similarities with some nuclei of early-type dwarf galaxies. Some of these objects could actually be stripped nuclei, possibly accreted during minor merger events.
We will present an exhaustive study of the most outstanding stellar systems associated with this galaxy. Indeed, some of them appear to be composed of more than one stellar population. We will show the analysis of its most relevant physical properties and its star formation history, which we have obtained through the full spectral fitting technique. In this new approach, we propose to obtain a more detailed picture of the recent past of this galaxy, and its different fusion events, which have given rise to a complex family of stellar systems.
#159 |
What drives the corpulence of galaxies? I. The formation of compact dwarf galaxies in TNG50
Abhner de Almeida
1
;
Gary Mamon
2
1 - Instituto de Astronomia, Geofisica e Ciencias Atmosfericas.
2 - Institut d Astrophysique de Paris.
Resumo:
Dwarf galaxies have a variety of sizes (stellar half-mass radii), at given stellar mass, in the present-day Universe. This suggests different scenarios of evolution according to their final size. In this work, we compare the evolution of compact and normal dwarf galaxies in the Illustris TNG50 cosmological hydrodynamical simulation. We denote \textit{Compact} those dwarf galaxies ($\log (M / M_\odot)$ between 8.3 and 9.3) that end up in the low-size ($r_{1/2} < 450$ pc) branch at $z$=0. We then compare the median evolution of relevant physical parameters and radial profiles to understand the different evolution of the \textit{Compact} population. In TNG50, \textit{Compact} galaxies are rounder at $z=0$ and their current environments are fairly similar. However, at $z \sim 1$, the sizes (half-mass radii of the stellar component) of their most massive progenitors begin to decrease relative to those of normals, while their gas half-mass-radii and stellar masses evolve similarly to those of normal galaxies. This is related to star formation concentrated (suppressed) in the inner (outer) region of the galaxy, which is due to efficient gas infall associated with the lower density environment and fewer interactions for the \textit{Compact} galaxies that otherwise pump angular momentum into normal galaxies. Their low merger rate also leads to lower black hole occupation fractions and mass, and AGN activity, but these effects appear to be secondary compared to the lack of interactions and mergers. In TNG50, the formation of \textit{Compact} galaxies is driven by the lack of mergers and interactions, in contrast with the popular idea of merger-driven compaction at high redshift for more massive compact star-forming galaxies.
#595 |
The cluster initial mass function of the M82 disk Super Star Clusters
Bolivia Cuevas Otahola
1
;
Divakara Mayya
2
;
Jesus Arriaga Hernandez
1
;
Ivanio Puerari
2
;
Gustavo Bruzual
3
1 - Benemerita Universidad Autonoma de Puebla.
2 - Instituto Nacional de Astrofisica, Optica y Electronica.
3 - Instituto de Radioastronomia y Astrofisica.
Resumo:
Super Massive Clusters (SSCs) are thought to be the progenitors of Globular Clusters (GCs) due to their similar masses and densities. One way to test such a link is via the Cluster Mass Function (CMF), related to the Cluster Luminosity Function (CLF) via the mass-to-light ratio. In particular, the Cluster Initial Mass Function (CIMF) can be established from studies of young clusters (age$\sim$ 1—10 Myr). Several studies have reported a power-law CIMF with an index of 2. However, the GCs CLF has been found to follow a log-normal function. Since, the CLF is a proxy of the CMF, a change from power-law to log-normal is expected to occur due to evolution to support the link between SSCs and GCs. Hence, a large population of SSCs is required to study whether SSCs follow power-law or log-normal functions. The prototype starburst galaxy M82 harbors $\sim$400 almost coeval SSCs (100-300 Myr) in the disk, offering an opportunity to characterize the CIMF of the observed present-day CMF. We carry out the dynamical and photometric evolution of the CMF assuming the clusters move in circular orbits under the gravitational potential of M82 using the semi-analytical simulation code EMACSS. We explore power-law and log-normal functions for the CIMFs and populate the clusters in the disk assuming uniform, power-law, and exponential radial distribution functions. We find that the observed CMF is best produced by a CIMF that is power-law in form with an index of 1.8, for a power-law radial distribution function. We establish that the observed turn-over in the present-day CMF is the result of observational incompleteness rather than due to dynamically induced effects, or an intrinsically log-normal CIMF, as was proposed for the fossil starburst region B of this galaxy. Our simulations naturally reproduce the mass-radius relation observed for a sub-sample of M82 SSCs.
12:45 - 14:30
LUNCH
14:30 - 15:20
Plenary Review Talk
Invited Speaker:
Marcelo Lopez Fuentes
- Instituto de Astronomía y Física del Espacio
(Argentina)
[cv]
Marcelo Lopez Fuentes
Instituto de Astronomía y Física del Espacio
Curriculum Vitae:
Marcelo Lopez Fuentes obtained his PhD in Physics from the University of Buenos Aires (UBA). He is presently a Research Scientist of the National Council for Scientific Research of Argentina (CONICET) at the Institute of Astronomy and Space Physics (IAFE, CONICET-UBA) in Buenos Aires. He developed postdoctoral and scientific exchange activities at the Observatory of Paris in Meudon, France, and at the Naval Research Laboratory and NASA in the USA. His main research interests are in Solar Physics, in particular the origin and evolution of magnetic structures and plasma dynamics of the solar atmosphere.
Chair: Julio Fernández
#240 |
The role of modeling and observations for a complete explanation of coronal heating
Marcelo López Fuentes
1
1 - Instituto de Astronomía y Física del Espacio (IAFE, CONICET-UBA).
Resumo:
The problem of how the solar corona is hundreds of times hotter than the underlying photosphere continues to be a subject of intense study and interest for the solar physics community. The motivation lies not only on having a detailed account of solar phenomena with potential impact on Earth’s spatial environment, but also on the implicit contribution to understanding the physics of low-density/high-temperature plasmas in other more general astrophysical scenarios. One of the main persisting challenges is that fundamental processes occur on spatial scales that are beyond the resolution power of instruments presently available. Therefore, a strong interaction between models and observations is necessary. From the side of modeling, the highly diverse spatial scales, from single particle gyroradii (cm to tens of m) to the structure of coronal magnetic loops (hundreds of Mm), make it impossible to include all of them in single numerical simulations, demanding instead the use of different approaches and physical formalism for different spatial scale regimes. Regarding observations, it is necessary to put under the same phenomenological frame diverse sets of data obtained in wavelengths spanning from radio to X-rays. In this talk we review the main aspects of the problem, its present state and some of the recent advances in understanding the underlying processes. We discuss also how future missions, instruments and computational tools are expected to contribute to respond key remaining questions.
15:20 - 15:50
Plenary Target Talk
Invited Speaker:
Mariana Andrea Cécere
- Instituto de Astronomía Teórica y Experimental
(Argentina)
[cv]
Mariana Andrea Cécere
Instituto de Astronomía Teórica y Experimental
Curriculum Vitae:
Doctora en Física, graduada de la Facultad de Matemática, Astronomía y Física de la Universidad Nacional de Córdoba.
Investigadora Adjunta del Instituto de Astronomía Teórica y Experimental (CONICET/UNC), y docente del Observatorio Astronómico de Córdoba (UNC).
Especialista en Física Solar. Su principal expertise se basa en el desarrollo y análisis de simulaciones numéricas de diferentes fenómenos de la atmósfera del Sol, tales como, oscilaciones de arcos coronales y filamentos quiescentes, ondas Moreton, supra-arcade downflows y determinación de la trayectoria y posibles deflexiones de eyecciones coronales de masa, de importancia para el estudio del clima espacia
Chair: Julio Fernández
#070 |
CME Deflections: A Brief Review and New Insights
Mariana Cécere
1
1 - Instituto de Astronomía Teórica y Experimental.
Resumo:
Recent research has demonstrated the significant role played by magnetic structures surrounding coronal mass ejection (CME) events in their initial development and progression. Active regions, coronal holes, pseudostreamers, and helmet streamers are key components of the corona that contribute to the deviation of CME trajectories from their radial path. Therefore, comprehensive observational studies, coupled with theoretical interpretations and numerical simulations, are vital in understanding the early evolution of CMEs and accurately determining their three-dimensional trajectory in the interplanetary medium. This approach is crucial for reducing errors in estimating the arrival time of geoeffective events. In this concise review, we compile from the theoretical, numerical, and observational investigations that have provided insights into the factors influencing CME deflection away from their typical radial trajectory.
15:50 - 16:30
COFFEE BREAK
16:30 - 18:00
J: Galaxies and Cosmology
Stellar and gas content
Chair: Rosa Amelia González
#561 |
Photospectral synthesis of galaxies in the middle age of the Universe
Victor Hugo Sasse
1
;
Roberto Cid Fernandes Junior
1
1 - Universidade Federal de Santa Catarina.
Resumo:
Detailed full spectral synthesis studies of the stellar populations in galaxies are usually restricted to the local Universe (z $\sim$ 0.1), where data is more abundant. From this kind of study, inferencess are made about the evolution of galaxies, a more direct way to study this evolution is through the analisis of galaxies at cosmologically interesting distances (high redshift). Spectroscopic observations from Large Early Galaxy Astrophysics Census (LEGA-C) using VLT telescope, of galaxies at redshift's around 0.6 - 1.0 allow spectral synthesis studies similar to those performed in the Local Universe, but for systems half as old. However, the spectral window of observation usually only covers about 3000 \AA , meaning that even with good quality, we don't have good quantity of spectral data. These spectras are complemented with photometric measurements from a wealth of sources (SUBARU, HST, among others) and this pan-spectral allows more reliable stellar populations adjustments than those based only on optical spectrum. The data cover a range of wavelengths from the U band, at $\lambda$ $\sim$ 3800 \AA , to the K band, in the infrared at $\lambda$ $\sim$ 21500 \AA , providing information for the blue and red ranges of wavelengths covered by VLT spectroscopy.
Photometric and spectroscopic data are adjusted simultaneously with the latest version of the STARLIGHT code. The photo-spectral fits obtained are excellent. The intrinsic properties (masses, average age and metallicity, extinction, star formation history) derived from these adjustments allow detailed studies of these objects. Here we present the method, adjustments and some preliminary results on the rejuvenation of quiescent galaxies.
#265 |
Star formation histories, morphology, and environment of galaxies in the local universe
David Pérez-Millán
1
;
Jacopo Fritz
1
;
Rosa Amelia González-Lópezlira
1
1 - Instituto de Radioastronomia y Astrofísica, UNAM.
Resumo:
One of the main questions faced by modern extragalactic astrophysics is about the origin of galactic properties. While stellar evolution drives the evolutionary paths and timescales of isolated galaxies, galaxies in clusters are subject to a whole range of processes and interactions that dramatically change this picture.
To shed light on these issues, we exploit optical spectra from the WINGS survey and its extension OmegaWINGS ($0.04 < z < 0.07$). We use stellar population synthesis techniques to analyze these spectra and obtain properties related to the stars in the galaxies, e.g., stellar mass, stellar ages, star formation rates, and star formation histories. The data include both cluster member and non-member (field) galaxies, which allows us to quantify the effect of the environment.
Our results show that, although the cluster environment eventually shuts down star formation, several mechanisms at play may instead temporarily enhance it. For example, ram pressure and close encounters with other galaxies can initiate star formation; however, this further accelerates gas depletion. Likewise, it is of fundamental importance to take morphology into account: while cluster late-type galaxies do follow the main sequence of star-forming galaxies, early type galaxies display some level of star formation as well, likely triggered by hydrodynamic interactions with the intercluster gas or gravitational interactions with other cluster members. However, the star formation rates of elliptical and S$0$ galaxies do not show a significant correlation with their stellar mass. Hence, their (very) local environment is the one that shapes the properties of their recent stellar populations, while the global influence of the cluster is likely a secondary agent, resulting from the sum of local ones. In short, the influence of the environment, modulated by the local density of galaxies, is imprinted on the galaxy morphology.
#082 |
Stellar populations and emission lines in S-PLUS galaxies
Júlia Thainá Batista
1
;
Claudia Mendes de Oliveira
2
;
Analía Smith Catelli
3
;
Roberto Cid Fernandes
1
1 - Universidade Federal de Santa Catarina.
2 - Instituto de Astronomia, Geofísica e Ciências Atmosféricas da USP.
3 - Instituto de Astrofísica de La Plata.
Resumo:
We present tests of a new method to simultaneously estimate stellar population and emission line (EL) properties of galaxies out of S-PLUS photometry. The technique uses the Alstar code, updated with an empirical prior which greatly improves its ability to estimate ELs using only the survey’s 12 bands. The tests compare the output of (noise-perturbed) synthetic photometry of SDSS galaxies to properties derived from previous full spectral fitting and detailed EL analysis. For realistic signal-to-noise ratios, stellar population properties are recovered to better than 0.2 dex in masses, mean ages, metallicities, and ±0.2 mag for the extinction. More importantly, ELs are recovered remarkably well for a photometric survey. We obtain input-output dispersions of 0.05–0.2 dex for the equivalent widths of $[\mathrm{O}\,\textsc{ii}]$, $[\mathrm{O}\,\textsc{iii}]$, H$\beta$, H$\alpha$, $[\mathrm{N}\,\textsc{ii}]$, and $[\mathrm{S}\,\textsc{ii}]$, and even better for lines stronger than $\sim 5 \mathring{A}$. This is achieved by exploring two facts: (1) Because, for the redshifts explored here, H$\alpha$ and $[\mathrm{N}\,\textsc{ii}]$ fall in a narrow band (J0660), their combined equivalent width is always well recovered, even when $[\mathrm{N}\,\textsc{ii}]$/H$\alpha$ is not. (2) We know from the SDSS that WH$\alpha$+$[\mathrm{N}\,\textsc{ii}]$ correlates with $[\mathrm{N}\,\textsc{ii}]$/H$\alpha$ and thus can be used to diagnose if a galaxy belongs to the left or right wing in the classical BPT diagnostic diagram. We combine these two facts in a prior which restricts the EL space available for the fits, obtaining excellent results. Example applications to integrated light and spatially resolved data are also presented. We combine these two facts in a prior which restricts the EL space available for the fits. Example applications to integrated light and spatially resolved data are also presented, including a comparison with results obtained by means of integral field spectroscopy with MUSE.
#287 |
Stellar properties of ultra-diffuse galaxies in TNG50 simulation
Jose Benavides
1
;
Laura Sales
1
;
Mario Abadi
2
1 - University of california, Riverside.
2 - IATE - CONICET.
Resumo:
Using data from the TNG50 simulation we study the stellar properties of a sample of simulated ultra-diffuse galaxies (UDGs) in groups and clusters. We find that, on average, UDGs are approximately 70\% less enriched in [Fe/H] compared to the non-UDG population at fixed stellar mass. Also, simulated UDGs are predicted to be more alpha-enhanced, as indicated by [Mg/Fe], than the non-UDG sample at fixed metallicity. The simulations demonstrate a very steep negative gradient in metallicity with radius, indicating a difference from UDGs formed through internal mechanisms like feedback. This suggests that metallicity profiles might be used to identify the formation path of these objects. In terms of star formation histories, when distinguishing between quenched and star-forming satellites, UDGs and non-UDG dwarfs exhibit good agreement. However, UDGs generally tend to quench more rapidly than their non-UDG counterparts after infall, by approximately 1 Gyr. This could be attributed to more efficient ram-pressure stripping caused by the smaller gravitational restoring force resulting from the extended baryonic distribution in UDGs.
#051 |
SMARTY: The mileS geMini neAr infRared sTellar librarY
Michele Bertoldo
1
;
Rogério Riffel
1
;
Marina Trevisan
1
;
Natacha Zanon Dametto
2
;
Luis Dahmer-Hahn
3
;
Paula Coelho
4
;
Lucimara Martins
5
;
Ana Chie Santos
1
;
Alexandre Vazdekis
2
;
Daniel Ruschel-Dutra
6
;
Alan Alves Brito
1
;
Tatiana Moura
4
;
Rogemar A. Riffel
7
;
Alberto Rodríguez-Ardila
8
;
Alejandro Romero
1
1 - Universidade Federal do Rio Grande do Sul.
2 - Instituto de Astrofísica de Canarias, Universidad de La Laguna.
3 - Shanghai Astronomical Observatory - Chinese Academy of Sciences.
4 - Universidade de São Paulo.
5 - NAT – Universidade Cidade de São Paulo/Universidade Cruzeiro do Sul.
6 - Universidade Federal de Santa Catarina.
7 - Universidade Federal de Santa Maria.
8 - Laboratório Nacional de Astrofísica, Instituto Nacional de Pesquisas Espaciais.
Resumo:
Most of the observed galaxies cannot be resolved and therefore are studied through the evolutionary synthesis of simple stellar populations (SSPs). Spectroscopic observations are increasingly being directed towards the near-infrared (NIR, e.g. James Webb Telescope), thus we need to understand the stellar populations that dominate the galaxies' light in this spectral region. However, due to observational and theoretical difficulties, different simple stellar population models differ in their predictions in the NIR. In this context, having reliable stellar libraries in the NIR is essential as this is the most important ingredient to develop reliable stellar population synthesis models. In this work we present a 0.35-2.4 $\mu$m stellar spectral library composed by 31 stars observed with the Gemini Near-IR Spectrograph (GNIRS) on the 8.1 m Gemini North telescope in Mauna Kea, Hawaii. These stars are present in the MILES library, and thus various parameters derived from the optical are available. Furthermore, out of those, 26 are presented for the first time in the NIR.
We compare these data with the theoretical Göttingen Spectral Library (GSL) using two different methods: in the first, we selected the GSL model which returned the lowest $\chi^2$; and in the second, we made a spectral fitting using Starlight code, which combined GSL models within a selected base that best describes the observed spectrum for the optical and NIR region. In this work, we found that the spectral continuum is well represented, but the absorption lines are not, indicating the need for better atomic line lists. The SMARTY library will be made available and can be incorporated into future stellar population models.
