A5029162322- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Astrophysical Phenomena and Observations
- History and Developments in Astronomy
- Remote Sensing in Agriculture
- Plant Water Relations and Carbon Dynamics
- Adaptive optics and wavefront sensing
- Cosmology and Gravitation Theories
- Astronomical and nuclear sciences
- Black Holes and Theoretical Physics
- Impact of Light on Environment and Health
- Radio Astronomy Observations and Technology
- Geophysics and Gravity Measurements
- earthquake and tectonic studies
- Solar and Space Plasma Dynamics
- Geological and Geochemical Analysis
- High-pressure geophysics and materials
- Tribology and Lubrication Engineering
- Advanced Fluorescence Microscopy Techniques
- Historical Astronomy and Related Studies
University of La Serena
2017-2024
Max Planck Institute for Astrophysics
2015-2019
Max Planck Society
2015-2019
Max Planck Institute for Astronomy
2019
Astronomical Institute of the Slovak Academy of Sciences
2013-2015
University of Michigan
2012-2014
University of Groningen
2009-2011
Astronomy and Space
2009
Istituto Nazionale di Geofisica e Vulcanologia
2005
We have measured stellar photometry with the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) and Advanced for Surveys (ACS) in near ultraviolet (F275W, F336W), optical (F475W, F814W), infrared (F110W, F160W) bands 117 million resolved stars M31. As part of Panchromatic Andromeda Treasury (PHAT) survey, we simultaneous point spread function fitting across all at source positions after precise astrometric image alignment (<5-10 milliarcsecond accuracy). In outer disk, reaches a...
We examine the stellar haloes of Auriga simulations, a suite thirty cosmological magneto-hydrodynamical high-resolution simulations Milky Way-mass galaxies performed with moving-mesh code AREPO. study halo global properties and radial profiles out to $\sim 150$ kpc for each individual galaxy. The are diverse in their masses density profiles; mean metallicity gradients; ages; shapes, reflecting stochasticity inherent accretion merger histories. A comparison observations nearby late-type shows...
We have examined the resolved stellar populations at large galactocentric distances along minor axis (from 10 kpc up to between 40 and 75 kpc), with limited major coverage, of six nearby highly-inclined Milky Way-mass disc galaxies using HST data from GHOSTS survey. select red giant branch stars derive halo density profiles. The projected profiles can be approximated by power laws slopes $-2$ $-3.7$ a diversity masses $1-6\times 10^{9}M_{\odot}$, or $2-14\%$ total galaxy masses. typical...
We present the discovery of a new dwarf galaxy, Hydra II, found serendipitously within data from ongoing Survey Magellanic Stellar History conducted with Dark Energy Camera on Blanco 4 m Telescope. The satellite is compact ( ± 11 pc) and faint 0.3), but well realm galaxies. stellar distribution II in color–magnitude diagram well-described by metal-poor () old (13 Gyr) isochrone shows distinct blue horizontal branch, some possible red clump stars, stars that are suggestive stragglers. At...
We use data from the HST Coma Cluster Treasury program to assess richness of Globular Systems (GCSs) 54 ultra-diffuse galaxies (UDGs), 18 which have a half-light radius exceeding 1.5 kpc. hierarchical Bayesian method tested on large number mock datasets account consistently for high and spatially varying background counts in Coma. These include both intra-cluster GCs (ICGCs), are disentangled population member probabilistic fashion. find no candidate GCS as rich that Milky Way, our sample...
ABSTRACT We explore the chemodynamical properties of a sample barred galaxies in Auriga magnetohydrodynamical cosmological zoom-in simulations, which form boxy/peanut (b/p) bulges, and compare these to Milky Way (MW). show that best reproduce stellar populations MW bulge have quiescent merger histories since redshift z ∼ 3.5: their last major occurs at $t_{\rm lookback}\gt 12\, \rm Gyr$, while subsequent mergers mass ratio ≤1:20, suggesting an upper limit few per cent for recently proposed...
The dwarf satellites of `giant' Milky Way (MW)-mass galaxies are our primary probes low-mass dark matter halos. number and velocities the satellite MW M31 initially puzzled galaxy formation theorists, but now reproduced well by many models. Yet, MW's M31's representative? Were models `overfit'? These questions motivate deep searches for outside Local Group. We present a survey `classical' ($M_{\star}$$\geqslant$4$\times$10$^5 M_{\odot}$) MW-mass M94 out to 150 kpc projected distance. find...
We study the stellar halo color properties of six nearby massive highly inclined disk galaxies using Hubble Space Telescope Advanced Camera for Surveys and Wide Field 3 observations in both F606W F814W filters from GHOSTS survey. The observed fields, placed along minor major axis each galaxy, probe outskirts out to projected distances ~ 50-70 kpc their galactic centre axis. 50% completeness levels magnitude diagrams are typically at two mag below tip red giant branch. find that all have...
Abstract We map the star formation history across M31 by fitting stellar evolution models to color–magnitude diagrams of each 83″ × (0.3 1.4 kpc, deprojected) region Panchromatic Hubble Andromeda Treasury (PHAT) survey outside innermost <?CDATA $6^{\prime} \times 12^{\prime} $?> portion. find that most occurred prior ∼8 Gyr ago, followed a relatively quiescent period until ∼4 subsequent episode about 2 and return relative quiescence. There appears be little, if any, structure visible for...
APOGEE is a high-resolution (R sim 22,000), near-infrared, multi-epoch, spectroscopic survey of the Milky Way. The second generation project, APOGEE-2, includes an expansion to Southern Hemisphere called APOGEE-2S. This enabled perform fully panoramic mapping all main regions Way; in particular, by operating H-band, uniquely able probe dust-hidden inner Way that are best accessed from Hemisphere. In this paper we present targeting strategy APOGEE-2S, with special attention documenting...
We observed two fields near M32 with the ACS/HRC on board Hubble Space Telescope, located at distances of about 1.8' and 5.4' (hereafter F1 F2, respectively) from center M32. To obtain a very detailed deep color-magnitude diagram (CMD) to look for short period variability, we obtained time-series imaging each field in 32-orbit-long exposures using F435W (B) F555W (V) filters, spanning temporal range 2 days per filter. focus our detection variability RR Lyrae variable stars, which represents...
Abstract We present a study of the three-dimensional (3D) structure Large Magellanic Cloud (LMC) using ∼2.2 million red clump (RC) stars selected from Survey MAgellanic Stellar History. To correct for line-of-sight dust extinction, intrinsic RC color and magnitude their radial dependence are carefully measured by internal nearly dust-free regions. These then used to construct an accurate 2D reddening map (165 deg 2 area with ∼10′ resolution) LMC disk 3D spatial distribution stars. An...
Abstract We present the physical characterization of FSR 1758, a new large, massive object very recently discovered in Galactic Bulge. The combination optical data from 2nd Gaia Data Release and DECam Plane Survey near-IR VISTA Variables Vía Láctea Extended led to clean sample likely members. Based on this integrated set, position, distance, reddening, size, metallicity, absolute magnitude, proper motion (PM) are measured. estimate following parameters: α = 17:31:12, δ −39:48:30 (J2000), D...
We measure the recent star formation history (SFH) across M31 using optical images taken with Hubble Space Telescope as part of Panchromatic Andromeda Treasury (PHAT). fit color–magnitude diagrams in ∼9000 regions that are ∼100 pc × 100 projected size, covering a 0.5 square degree area (∼380 kpc2, deprojected) NE quadrant M31. show SFHs vary significantly on these small spatial scales but there also coherent galaxy-wide fluctuations SFH back to ∼500 Myr, most notably M31's 10 kpc...
We use data of $\sim$13,000 stars from the SDSS/APOGEE survey to study shape bulge MDF within region $|\ell|\leq11^\circ$ and $|b|\leq13^\circ$, spatially constrained ${\rm R_{GC}\leq3.5}$ kpc. apply Gaussian Mixture Modeling Non-negative Matrix Factorization decomposition techniques identify optimal number properties components. find spatial variations (at [Fe/H]\geq-1}$ dex) are well represented as a smoothly varying contribution three overlapping components located at [Fe/H]=+$0.32$,...
We use magneto-hydrodynamical simulations of Milky Way-mass haloes from the Auriga project to examine properties surviving and destroyed dwarf galaxies that are accreted by these over cosmic time. show combined luminosity function dwarfs at infall is similar in various haloes, dominated dwarfs. There is, however, a strong dependence on time: have typically early times, $t_{infall}<6$ Gyr, whereas majority $t_{infall}>10$ Gyr survived present day. Because their late satellites today had...
ABSTRACT We use the SMASH survey to obtain unprecedented deep photometry reaching down oldest main-sequence turn-offs in colour–magnitude diagrams (CMDs) of Small Magellanic Cloud (SMC) and quantitatively derive its star formation history (SFH) using CMD fitting techniques. identify five distinctive peaks last 3.5 Gyr, at ∼3, ∼2, ∼1.1, ∼0.45 Gyr ago, one presently. compare these SFH Large (LMC), finding unequivocal synchronicity, with both galaxies displaying similar periods enhanced over...
Deep photometry of the Small Magellanic Cloud (SMC) stellar periphery (R=4 deg, 4.2 kpc) is used to study its line-of-sight depth with red clump (RC) stars. The RC luminosity function affected little by young (<1 Gyr) blue-loop stars in these regions because their main-sequence counterparts are not observed color magnitude diagrams. SMC's eastern side found have a large (~23 while western has much shallower (~10 kpc), consistent previous photographic plate results. We use model SMC...
We characterize the contribution from accreted material to galactic discs of Auriga Project, a set high-resolution magnetohydrodynamic cosmological simulations late-type galaxies performed with moving-mesh code arepo. Our goal is explore whether significant (or ex situ) stellar component in Milky Way disc could be hidden within near-circular orbit population, which strongly dominated by stars born situ. One-third our models shows situ but this fraction would larger if constraints on orbital...
Abstract The Large and Small Magellanic Clouds are unique local laboratories for studying the formation evolution of small galaxies in exquisite detail. Survey MAgellanic Stellar History (SMASH) is an NOAO community Dark Energy Camera (DECam) survey mapping 480 deg 2 (distributed over ∼2400 square degrees at ∼20% filling factor) to ∼24th mag ugriz . primary goals SMASH identify low surface brightness stellar populations associated with halos tidal debris Clouds, derive spatially resolved...
Galaxies with Milky Way-like stellar masses have a wide range of bulge and black hole masses; in turn, these correlate other properties such as star formation history. While many processes may drive formation, major minor mergers are expected to play crucial role. Stellar halos offer novel robust measurement galactic merger history; cosmologically-motivated models predict that larger satellites produce more massive, higher metallicity halos, reproducing the recently-observed halo...
We study the galactic bulges in Auriga simulations, a suite of thirty cosmological magneto-hydrodynamical zoom-in simulations late-type galaxies Milky Way-sized dark matter haloes performed with moving-mesh code AREPO. aim to characterize bulge formation mechanisms this large simulated at high resolution fully context. The show variety their shapes,sizes and histories. According observational classification criteria, such as Sersic index degree ordered rotation, majority can be classified...
We study the properties of stellar populations in M81's outermost part, which hereafter we will term halo, using HST ACS/WFC observations 19 fields from GHOSTS survey. The observed probe halo out to a projected distance ~ 50 kpc galactic center. Each field was both F606W and F814W filters. 50% completeness levels color magnitude diagrams (CMDs) are typically at 2 mag below tip red giant branch (TRGB). Fields distances closer than 15 show evidence disk-dominated whereas larger mostly...
The Panchromatic Hubble Andromeda Treasury (PHAT) survey is an on-going Space Telescope (HST) multi-cycle program to obtain high spatial resolution imaging of one-third the M31 disk at ultraviolet through near-infrared wavelengths. In this paper, we present first installment PHAT stellar cluster catalog. When completed, catalog will be among largest and most comprehensive surveys resolved star clusters in any galaxy. exquisite achieved with HST has allowed us identify hundreds new that were...
Abstract We explore the stellar structure of Large Magellanic Cloud (LMC) disk using data from Survey MAgellanic Stellar History and Dark Energy Survey. detect a ring-like overdensity in red clump star count map at radius ∼6° (∼5.2 kpc LMC distance) that is continuous over ∼270° position angle only limited by current coverage. The shows an amplitude up to 2.5 times higher than underlying smooth disk. This might be related multiple arms found de Vaucouleurs. find spatial correlation with...