A5084825640- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astronomical and nuclear sciences
- Adaptive optics and wavefront sensing
- Genomics and Phylogenetic Studies
- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- History and Developments in Astronomy
- Genetic diversity and population structure
- Atmospheric Ozone and Climate
- Isotope Analysis in Ecology
- Spectroscopy and Laser Applications
- Space Science and Extraterrestrial Life
- Biochemical and Structural Characterization
- Solar and Space Plasma Dynamics
- Geological and Geophysical Studies
- Earth Systems and Cosmic Evolution
- Plant Diversity and Evolution
- Cephalopods and Marine Biology
- Methane Hydrates and Related Phenomena
Universidad de Santiago de Chile
2024-2025
Millennium Institute of Astrophysics
2016-2024
Nucleus (Norway)
2024
Millennium Science Initiative
2024
Pontificia Universidad Católica de Chile
2016-2022
Observatoire de la Côte d’Azur
2014-2017
Centre National de la Recherche Scientifique
2014-2017
University of Trieste
2017
Osservatorio astronomico di Bologna
2017
Université Côte d'Azur
2014-2017
(Abridged) We analyzed the stellar parameters and radial velocities of ~1200 stars in five bulge fields as determined from Gaia-ESO survey data (iDR1). use VISTA Variables The Via Lactea (VVV) photometry to obtain reddening values by using a semi-empirical T_eff-color calibration. From Gaussian decomposition metallicity distribution functions, we unveil clear bimodality all fields, with relative size components depending specific position on sky. In agreement some previous studies, find mild...
Context. Several recent studies have demonstrated that the Galactic bulge hosts two components with different mean metallicities, and possibly spatial distribution kinematics. As a consequence, both metallicity radial velocity of stars vary across lines sight.
The Galactic bulge is a massive, old component of the Milky Way. It known to host bar, and it has recently been demonstrated have pronounced boxy/peanut structure in its outer region. Several independent studies suggest presence more than one stellar populations bulge, with different origins relative fraction changing across area. This first series papers presenting results Giraffe Inner Bulge Survey, carried out at ESO-VLT multifibre spectrograph FLAMES. Spectra ~5000 red clump giants 24...
We investigate the inner regions of Milky Way with a sample unprecedented size and coverage thanks to APOGEE DR16 Gaia EDR3 data. Our Galactic has more than 26,000 stars within $|X_{\rm Gal}| <5$ kpc, $|Y_{\rm <3.5$ $|Z_{\rm <1$ we also make analysis for foreground-cleaned sub-sample 8,000 representative bulge-bar populations. The Galaxy shows clear chemical discontinuity in key abundance ratios [$\alpha$/Fe], [C/N], [Mn/O], probing different enrichment timescales, which suggests star...
Abstract The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is a dual-hemisphere, near-infrared (NIR), spectroscopic survey with the goal of producing chemodynamical mapping Milky Way. targeting for APOGEE-2 complex and has evolved time. In this paper, we present updates additions to initial strategy APOGEE-2N presented in Zasowski et al. (2017). These modifications come two implementation modes: (i) “Ancillary Science Programs” competitively awarded Sloan Digital Sky...
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...
Abridged: We used the fourth internal data release of Gaia-ESO survey to characterize bulge chemistry, spatial distribution, kinematics, and compare it chemically with thin thick disks. The sample consist on ~2500 red clump stars in 11 fields ($-10^\circ\leq l\leq+8^\circ$ $-10^\circ\leq b\leq-4^\circ$), a set ~6300 disk selected for comparison. MDF is confirmed be bimodal across whole sampled area, metal-poor dominating at high latitudes. metal-rich exhibit bar-like kinematics display...
We present an overview of the distributions 11 elemental abundances in Milky Way's inner regions, as traced by APOGEE stars released part SDSS Data Release 14/15 (DR14/DR15), including O, Mg, Si, Ca, Cr, Mn, Co, Ni, Na, Al, and K. This sample spans ~4000 with R_GC<4 kpc, enabling most comprehensive study to date these their variations within innermost few kiloparsecs Way. describe observed abundance patterns ([X/Fe]-[Fe/H]), compare previous literature results at solar Galactic radius,...
Baade's window (BW) is one of the most observed Galactic bulge fields in terms chemical abundances. Due to its low and homogeneous interstellar absorption it considered as a calibration field for studies. In era large spectroscopic surveys, such BW are necessary cross calibrate stellar parameters individual abundances APOGEE survey. We use stars derive their metallicity distribution function (MDF) abundances, $\alpha$- iron-peak elements ASPCAP pipeline (DR13), well age BW. determine MDF...
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]=+$0.32$,...
High resolution (R$\sim$22,500) spectra for 400 red clump giants, in four fields within $\rm -4.8^{\circ} \lesssim b -3.4^{\circ}$ and -10^{\circ} l +10^{\circ}$, were obtained the GIRAFFE Inner Bulge Survey (GIBS) project. To this sample we added another $\sim$ stars Baade's Window, observed with identical instrumental configuration. We constructed metallicity distributions entire sample, as well each field individually, order to investigate presence of gradients or field-to-field...
The nuclear stellar disc (NSD) is, together with the star cluster (NSC) and central massive black hole, one of main components in parts our Milky Way. However, until recently, only few studies content NSD have been obtained due to extreme extinction crowding. With a dedicated KMOS (VLT, ESO) spectroscopic survey, we study kinematics global metallicities based on observations K/M giant stars. We trace radial velocities which were derived spectral indices (Na I CO) along compare those Galactic...
<title>Abstract</title> The nature and formation history of our Galaxy's largest most enigmatic stellar cluster, known as Omega Centauri (oCen) remains debated. Here, we offer a novel approach to disentangling the complex populations within oCen based on phylogenetics methodologies from evolutionary biology. These include Gaussian Mixture Model Neighbor-Joining clustering algorithms applied set chemical abundances members. Instead using classical in astronomy grouping them into separate...
In this work, we study the formation and chemical evolution of Galactic bulge with particular focus on abundance pattern ([Mg/Fe] vs. [Fe/H]), metallicity age distribution functions. We consider detailed models for inner disc, aim shedding light connection between these components origin stars. particular, first present a model assuming fast intense star formation, majority stars forming timescale less than 1 Gyr. Then analyze possibility two distinct stellar populations in bulge, as...
The Galactic bulge has a bimodal metallicity distribution function: different kinematic, spatial, and, potentially, age distributions characterize the metal-poor and metal-rich components. Despite this observed dichotomy, which argues for formation channels those stars, of stars in $\alpha$-abundance versus plane been found so far to be rather smooth single sequence. We use data from fourteenth release APOGEE spectroscopic survey (DR14) investigate Mg abundance (as tracer...
Thanks to the recent wide-area photometric surveys, number of star cluster candidates have risen exponentially in last few years. Most detections, however, are based only on presence an overdensity stars a given region, or variable stars, regardless their distance. As candidates, detection has not been dynamically confirmed. Therefore, it is currently unknown how many, and which ones, published true clusters, ones chance alignments. We present method detect confirm clusters spatial...
Context: In the last six years, VVV survey mapped 562 sq. deg. across bulge and southern disk of Galaxy. However, a detailed study these regions, which includes $\sim 36$ globular clusters (GCs) thousands open is by no means an easy challenge. High differential reddening severe crowding along line sight makes highly hamper to reliably distinguish stars belonging different populations and/or systems. Aims: The aim this separate that likely belong Galactic GC NGC 6544 from its surrounding...
We take advantage of the Gaia-ESO Survey iDR4 bulge data to search for abundance anomalies that could shed light on composite nature Milky Way bulge. The alpha-elements (Mg, Si, and whenever available, Ca) abundances, their trends with Fe abundances have been analysed a total 776 stars. In addition, aluminum ratio Mg also examined. Our analysis reveals existence low-alpha element stars respect standard sequence in [alpha/Fe] vs. [Fe/H] plane. 18 objects present deviations ranging from 2.1...
Abstract Deep near-IR images from the VISTA Variables in Vía Láctea (VVV) Survey were used to search for RR Lyrae stars within 100 arcmin Galactic Center. A large sample of 960 type ab (RRab) discovered. catalog is presented featuring positions, magnitudes, colors, periods, and amplitudes sample, addition estimated reddenings, distances, metallicities, measured individual relative proper motions. We use reddening-corrected Wesenheit defined as <?CDATA ${W}_{{K}_{s}}={K}_{s}-0.428\times...
We present elemental abundance analysis of high-resolution spectra for five giant stars, deriving Fe, Mg, Al, C, N, O, Si and Ce abundances, spatially located within the innermost regions bulge globular cluster NGC 6522, based on H-band taken with multi-object APOGEE-north spectrograph from SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. Of candidates, two previously unremarked stars are confirmed to have second-generation (SG) patterns, basic pattern...