A5018914073- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Astrophysics and Star Formation Studies
- Particle physics theoretical and experimental studies
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Neutrino Physics Research
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Relativity and Gravitational Theory
- Adaptive optics and wavefront sensing
- Plant Water Relations and Carbon Dynamics
- Dark Matter and Cosmic Phenomena
- Remote Sensing in Agriculture
- Noncommutative and Quantum Gravity Theories
- Geophysics and Gravity Measurements
- CCD and CMOS Imaging Sensors
- Phase Equilibria and Thermodynamics
- Spectroscopy and Laser Applications
- Advanced Differential Geometry Research
- Calibration and Measurement Techniques
- Radio Astronomy Observations and Technology
Instituto de Astrofísica de Canarias
2012-2024
Universidad de La Laguna
2012-2024
Universidad Autónoma de Nuevo León
2023
University of California, Santa Cruz
2016-2022
Max Planck Institute for Astronomy
2018-2021
Universitat Politècnica de València
2020
Max Planck Society
2018
Consejo Superior de Investigaciones Científicas
1999-2015
IAC (United States)
2014
European Organization for Nuclear Research
2008
The hypothesis of a universal initial mass function (IMF) -- motivated by observations in nearby stellar systems has been recently challenged the discovery systematic variation IMF with central velocity dispersion, {\sigma}, early-type galaxies (ETGs), towards an excess low-mass stars high-{\sigma} galaxies. This trend derived so far from integrated spectra, and remains unexplained at present. To test whether such depends on local properties within galaxy, we have obtained new, extremely...
Variations in the stellar initial mass function (IMF) have been invoked to explain spectroscopic and dynamical properties of early-type galaxies (ETGs). However, no observations yet able disentangle physical driver. We analyze here a sample 24 ETGs drawn from CALIFA survey, deriving homogeneous way their population kinematic properties. find that local IMF is tightly related metallicity, becoming more bottom-heavy toward metal-rich populations. Our result, combined with galaxy...
ABSTRACT Ultra-diffuse galaxies (UDGs) have the sizes of giants but luminosities dwarfs. A key to understanding their origins comes from total masses, low surface brightnesses ( 25.0) generally prohibit dynamical studies. Here, we report first such measurements for a UDG (VCC 1287 in Virgo cluster), based on its globular cluster system dynamics and size. From seven GCs measure mean systemic velocity v sys = km s −1 , thereby confirming association. We dispersion within 8.1 kpc, corresponding...
At present, the main challenge to interpretation of variations in gravity-sensitive line strengths as driven by a non-universal initial mass function (IMF), lies understanding effect other parameters describing unresolved stellar populations, such elemental abundance ratios. We combine various TiO-based, IMF-sensitive indicators optical and NIR spectral windows, along with FeH-based Wing-Ford band break this degeneracy. obtain significant radial trend IMF slope XSG1, massive early-type...
We consider solutions of six dimensional Einstein equations with two compact dimensions. It is shown that one can introduce 3-branes in this background such a way the effective four cosmological constant completely independent brane tensions. These tensions are arbitrary, without requiring any fine tuning. must, however, tune bulk parameters order to obtain sufficiently small value for observable constant. comment description effect at energies below compactification scale.
We look at general brane worlds in six-dimensional Einstein-Gauss-Bonnet gravity. find the matching conditions for world, which remarkably give precisely four-dimensional Einstein equations brane, even when extra dimensions are noncompact and have infinite volume. Relaxing regularity of curvature vicinity or having a thick gives rise to an additional term containing information on brane's embedding bulk. comment relevance these results possible solution cosmological constant problem.
We study spherically symmetric solutions in f(R) theories and its compatibility with local tests of gravity. start by clarifying the range validity weak field expansion show that for many models proposed to address Dark Energy problem this breaks down realistic situations. This invalidates conclusions several papers make inappropriate use expansion. For stable modify gravity only at small curvatures we find when asymptotic background curvature is large approximately recover Einstein through...
In this second paper of the series, we study with new Keck/DEIMOS spectra stellar populations seven spectroscopically confirmed ultra-diffuse galaxies (UDGs) in Coma cluster. We find intermediate to old ages (~ 7Gyr), low metallicities ([Z/H] ~ -0.7dex) and mostly super-solar abundance patterns ([Mg/Fe] 0.13dex). These properties are similar those low-luminosity (dwarf) inhabiting same area cluster most consistent being continuity mass scaling relations more massive galaxies. UDGs' star...
Massive relic galaxies formed the bulk of their stellar component before z~2 and have remained unaltered since then. Therefore, they represent a unique opportunity to study in great detail frozen population properties those that populated primitive Universe. We combined optical near-infrared line-strength indices order infer, out 1.5 Reff, IMF nearby massive galaxy NGC 1277. The this is bottom-heavy at all radii, with fraction low-mass stars being least factor two larger than found Milky...
We confirm two new local massive relic galaxies, i.e. untouched survivors of the early Universe population: Mrk 1216 and PGC 032873. Both show peaked formation events within very short time-scales (<1 Gyr) thus old mean mass-weighted ages (∼13 Gyr). Their star histories remain virtually unchanged out to several effective radii, even when considering steeper initial-mass-function values inferred ∼3 radii. morphologies, kinematics density profiles are like those found in z > 2 population,...
In this letter we describe how use stellar dynamics information to constrain the shape of IMF in a sample 27 early-type galaxies from CALIFA survey. We obtain dynamical and mass-to-light ratios, $\Upsilon_\mathrm{dyn}$ $\Upsilon_{\ast}$, over homogenous aperture 0.5~$R_{e}$. constraint $\Upsilon_\mathrm{dyn} \ge \Upsilon_{\ast}$ test two shapes within framework extended MILES population models. rule out single power law for 75% our sample. Conversely, find that double with varying high-mass...
Understanding the peculiar properties of Ultra Diffuse Galaxies (UDGs) via spectroscopic analysis is a challenging task requiring very deep observations and exquisite data reduction. In this work we perform one most complete characterisations stellar component UDGs to date using optical from OSIRIS at GTC. We measure radial rotation velocities, star formation histories (SFH) mean population parameters, such as ages metallicities, for sample five UDG candidates in Coma cluster. From confirm...
To investigate star formation and assembly processes of massive galaxies, we present here a spatially-resolved stellar populations analysis sample 45 elliptical galaxies (Es) selected from the CALIFA survey. We find rather flat age [Mg/Fe] radial gradients, weakly dependent on effective velocity dispersion galaxy within half-light radius. However, our shows that metallicity gradients become steeper with increasing dispersion. In addition, have homogeneously compared Es to nearby relic i.e.,...
The 31 brightest galaxies (m_B < 15 mag) inside the virial radius of Fornax cluster were observed from centres to outskirts with Multi Unit Spectroscopic Explorer on Very Large Telescope. These observations provide detailed high-resolution maps line-of-sight kinematics and line strengths stars ionised gas reaching 2-3 Re for 21 early-type 1-2 10 late-type galaxies. majority are regular rotators, eight hosting a kinematically distinct core. Only two slow rotators. mean age, total metallicity,...
Abstract Energy feedback, either from active galactic nuclei (AGNs) or supernovae, is required to understand galaxy formation within a Λ-cold dark matter cosmology. We study sample of 127 low-mass galaxies, comparing their stellar population properties the mass central supermassive black hole, in order investigate effect AGN feedback. find loose coupling between star history and hole mass, which seems suggest that activity does not dominate baryonic cooling galaxies. also break – σ relation...
ABSTRACT The TNG50 cosmological simulation produces X-ray emitting bubbles, shells, and cavities in the circumgalactic gas above below stellar discs of Milky Way- Andromeda-like galaxies with morphological features reminiscent eROSITA Fermi bubbles Galaxy. Two-thirds 198 MW/M31 analogues inspected at z = 0 show one or more large-scale, coherent overpressurized that impinge into gaseous halo. Some include a succession shells increasing size, ranging from few to many tens kpc. These are...
The centres of disc galaxies host a variety structures built via both internal and external processes. In this study, we constrain the formation evolution these central structures, in particular nuclear rings discs, by deriving maps mean stellar ages, metallicities [$\alpha$/Fe] abundances. We use observations obtained with MUSE integral-field spectrograph for TIMER sample 21 massive barred galaxies. Our results indicate that discs are part same physical component, constituting outer edge...
Nuclear star clusters (NSCs) are the densest stellar systems in Universe and found centres of all types galaxies. They thought to form via mergers such as ancient globular (GCs) that spiral centre a result dynamical friction or through in-situ formation directly at galaxy centre. There is evidence both paths occur, but relative contribution either channel their correlation with properties not yet constrained observationally. We aim derive dominant NSC for sample 25 nucleated galaxies, mostly...
The mechanism causing breaks in the radial surface brightness distribution of spiral galaxies is not yet well known. Despite theoretical efforts, there a unique explanation for these features and observational results are conclusive. In an attempt to address this problem, we have selected sample 34 highly inclined present both Sloan Digital Sky Survey Spitzer Stellar Structure Galaxies. We measured profiles five optical bands 3.6$\mu m$ band. also calculated color stellar mass density using...
Dedicated photometric and spectroscopic surveys have provided unambiguous evidence for a strong stellar mass-size evolution of galaxies within the last 10 Gyr. The likely progenitors today's most massive are remarkably small, disky, passive already assembled much their mass at redshift z=2. An in-depth analysis these objects, however, is currently not feasible due to lack high-quality, spatially-resolved data. In this paper, we present sample nearby compact elliptical (CEGs), which bear...
Abstract We present observational constraints on the stellar populations of two ultra-diffuse galaxies (UDGs) using optical through near-infrared (NIR) spectral energy distribution (SED) fitting. Our analysis is enabled by new Spitzer -IRAC 3.6 and 4.5 μ m imaging, archival prospector fully Bayesian SED fitting framework. sample contains one field UDG (DGSAT I), Virgo cluster (VCC 1287), dwarf elliptical for comparison 1122). find that optical–NIR colors three are significantly different...