G. Guiglion
A5075034834- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Astronomical and nuclear sciences
- Spectroscopy and Chemometric Analyses
- Pulsars and Gravitational Waves Research
- Spectroscopy Techniques in Biomedical and Chemical Research
- CCD and CMOS Imaging Sensors
- Galaxies: Formation, Evolution, Phenomena
- SAS software applications and methods
- Astrophysical Phenomena and Observations
- Remote Sensing in Agriculture
- Inertial Sensor and Navigation
- Phase Equilibria and Thermodynamics
- Spectroscopy and Laser Applications
- Surface and Thin Film Phenomena
- Chemical Thermodynamics and Molecular Structure
- Semiconductor materials and interfaces
- Silicon and Solar Cell Technologies
- Scientific Research and Discoveries
- Impact of Light on Environment and Health
Max Planck Institute for Astronomy
2022-2024
Leibniz Institute for Astrophysics Potsdam
2017-2024
Heidelberg University
2023-2024
Campbell Collaboration
2019
Lagrange Laboratory
2019
Observatoire de la Côte d’Azur
2013-2018
Centre National de la Recherche Scientifique
2012-2018
Université Côte d'Azur
2015-2016
The Gaia-ESO Survey is obtaining high-quality spectroscopic data for about 10^5 stars using FLAMES at the VLT. UVES high-resolution spectra are being collected 5000 FGK-type stars. These analyzed in parallel by several state-of-the-art methodologies. Our aim to present how these analyses were implemented, discuss their results, and describe a final recommended parameter scale defined. We also precision (method-to-method dispersion) accuracy (biases with respect reference values) of...
We present a catalogue of 362 million stellar parameters, distances, and extinctions derived from Gaia's early third data release (EDR3) cross-matched with the photometric catalogues Pan-STARRS1, SkyMapper, 2MASS, AllWISE. The higher precision Gaia EDR3 data, combined broad wavelength coverage additional surveys new stellar-density priors {\tt StarHorse} code allow us to substantially improve accuracy over previous photo-astrometric stellar-parameter estimates. At magnitude $G=14\, (17)$,...
In the last 15 years different ground-based spectroscopic surveys have been started (and completed) with general aim of delivering stellar parameters and elemental abundances for large samples Galactic stars, complementing Gaia astrometry. Among those surveys, Gaia-ESO Public Spectroscopic Survey (GES), only one performed on a 8m class telescope, was designed to target 100,000 stars using FLAMES ESO VLT (both Giraffe UVES spectrographs), covering all Milky Way populations, special focus open...
The eighteenth data release of the Sloan Digital Sky Surveys (SDSS) is first one for SDSS-V, fifth generation survey. SDSS-V comprises three primary scientific programs, or "Mappers": Milky Way Mapper (MWM), Black Hole (BHM), and Local Volume (LVM). This contains extensive targeting information two multi-object spectroscopy programs (MWM BHM), including input catalogs selection functions their numerous objectives. We describe production databases calibration- scientifically-focused...
Context. The Gaia-ESO Public Spectroscopic Survey is an ambitious project designed to obtain astrophysical parameters and elemental abundances for 100 000 stars, including large representative samples of the stellar populations in Galaxy, a well-defined sample 60 (plus 20 archive) open clusters. We provide internally consistent results calibrated on benchmark stars star clusters, extending across very wide range ages. This provides legacy data set intrinsic value, equally wide-ranging...
We present a semi-empirical, largely model-independent approach for estimating Galactic birth radii, r_birth, Milky Way disk stars. The technique relies on the justifiable assumption that negative radial metallicity gradient in interstellar medium (ISM) existed most of lifetime. Stars are projected back to their positions according observationally derived age and [Fe/H] with no kinematical information required. Applying our AMBRE:HARPS HARPS-GTO local samples, we show can constrain ISM...
In the current era of large spectroscopic surveys Milky Way, reference stars for calibrating astrophysical parameters and chemical abundances are paramount importance. We determine elemental Mg, Si, Ca, Sc, Ti, V, Cr, Mn, Co Ni our predefined set Gaia FGK benchmark stars. By analysing high-resolution high-signal to noise spectra taken from several archive datasets, we combined results eight different methods on a line-by-line basis. perform detailed homogeneous analysis systematic...
In the era of large-scale Galactic astronomy and multi-object spectroscopic stellar surveys, sample sizes number available chemical abundances have reached dimensions in which it has become difficult to process all information an effective manner. this paper we demonstrate use a dimensionality-reduction technique (t-distributed stochastic neighbour embedding; t-SNE) for analysing abundance-space distribution. While non-parametric non-linear behaviour makes estimate significance any...
Chemical abundances are an essential tool in untangling the Milky Way's enrichment history. However, evolution of interstellar medium abundance gradient with cosmic time is lost as a result radial mixing processes. For first time, we quantify many observational across Galactic disk function lookback and birth radius, $R_\text{birth}$. Using empirical approach, derive $R_\text{birth}$ estimates for 145,447 APOGEE DR17 red giant stars, based solely on their ages [Fe/H]. We explore detailed 6...
We present an empirical model of age-dependent photospheric lithium depletion, calibrated using a large, homogeneously-analysed sample 6200 stars in 52 open clusters, with ages from 2--6000 Myr and $-0.3<{\rm [Fe/H}]<0.2$, observed the Gaia-ESO spectroscopic survey. The is used to obtain age estimates posterior probability distributions measurements Li I 6708A equivalent width for individual (pre) main sequence $3000 < T_{\rm eff}/{\rm K} <6500$, domain where determination HR diagram either...
The last decade has seen a revolution in our knowledge of the Galaxy thanks to Gaia and asteroseismic space missions ground-based spectroscopic surveys. To complete this picture, it is necessary map ages its stellar populations. During recent years, dependence on time abundance ratios involving slow (s) neutron-capture $\alpha$ elements (called chemical-clocks) been used provide estimates ages, usually limited volume close Sun. We aim analyse relations chemical clocks Galactic disc extending...
Context. Bar formation and merger events can contribute to the rearrangement of stars within Galaxy in addition triggering star (SF) epochs. Super-metal-rich (SMR) found solar neighbourhood (SNd) be used as tracers such they are expected originate only inner have definitely migrated. Aims. We study a homogeneous large sample SMR SNd provide tighter constraints on epoch bar its impact Milky Way (MW) disc stellar populations. Methods. investigated 169 701 main sequence turnoff (MSTO) subgiant...
Context. JWST recently detected numerous disc galaxies at high redshifts, and there have been observations of cold z > 4 with ALMA. In the Milky Way (MW), recent studies highlight presence metal-poor stars in cold-disc orbits, suggesting an ancient disc. This prompts two fundamental questions. The first refers to time formation MW disc, second whether it originated as thin or larger velocity dispersion thick Aims. We carried out a chrono-chemo-dynamical study large sample precise stellar...
Understanding the history and evolution of Milky Way disc is one main goals modern astrophysics. We study velocity dispersion behaviour Galactic stars as a function [Mg/Fe] ratio, which can be used proxy relative age. This key relation essential to constrain formation mechanisms stellar populations well cooling processes. recommended parameters chemical abundances 7800 FGK field from second internal data release Gaia-ESO Survey. These were observed with GIRAFFE spectrograph, cover large...
We exploit the unique characteristics of a sample open clusters (OCs) and field stars for which high-precision 7Li abundances stellar parameters are homogeneously derived by Gaia-ESO Survey (GES). derive possibly undepleted 26 OCs star forming regions with ages from young to old spanning large range Galactocentric distances, allows us reconstruct local late Galactic evolution lithium as well its current abundance gradient along disc. Field added look further back in time constrain other...
The Gaia -ESO Survey is a public spectroscopic survey that targeted ≳10 5 stars covering all major components of the Milky Way from end 2011 to 2018, delivering its final release in May 2022. Unlike other surveys, only observed across spectral types with dedicated, specialised analyses: O ( T eff ~ 30 000–52 000 K) way K-M (≳3500 K). physics throughout these stellar regimes varies significantly, which has previously prohibited any detailed comparisons between significantly different types....
Context. In June 2022, Gaia DR3 provided the astronomy community with about one million spectra from Radial Velocity Spectrometer (RVS) covering CaII triplet region. next data releases, we anticipate number of RVS to successively increase several 10 eventually more than 200 spectra. Thus, stellar are projected be produced on an ‘industrial scale’, numbers well above those for current and anticipated ground-based surveys. However, one-third published have 15 ≤ S /N 25 per pixel such that they...
We investigate, using the Gaia-ESO Survey internal Data-Release 2, properties of double sequence Milky Way discs (defined chemically as high-alpha and low-alpha populations), discuss their compatibility with defined by other means such metallicity, kinematics or positions. This investigation uses two different approaches: in velocity space for stars located extended Solar neighbourhood, chemical at ranges Galactocentric radii heights from plane. The separation we find allows us to a novel...
The chemical evolution of lithium in the Milky Way represents a major problem modern astrophysics. Indeed, is, on one hand, easily destroyed stellar interiors, and, other produced at some specific evolutionary stages that are still not well constrained. goal this paper is to investigate content stars order put constraints enrichment our Galaxy, particular both thin and thick discs. Thanks high-resolution spectra from ESO archive high quality atmospheric parameters, we were able build massive...
(Abridged) The Maunakea Spectroscopic Explorer (MSE) is an end-to-end science platform for the design, execution and scientific exploitation of spectroscopic surveys. It will unveil composition dynamics faint Universe impact nearly every field astrophysics across all spatial scales, from individual stars to largest scale structures in Universe. Major pillars program MSE include (i) ultimate Gaia follow-up facility understanding chemistry distant Milky Way, including outer disk stellar halo...
Simpson's paradox, or Yule-Simpson effect, arises when a trend appears in different subsets of data but disappears reverses these are combined. We describe here seven cases this phenomenon for chemo-kinematical relations believed to constrain the Milky Way disk formation and evolution. show that interpreting trends relations, such as radial vertical chemical abundance gradients, age-metallicity relation, metallicity-rotational velocity relation (MVR), can lead conflicting conclusions about...
Context. With its origin coming from several sources (Big Bang, stars, cosmic rays) and given strong depletion during stellar lifetime, the lithium element is of great interest as chemical evolution in Milky Way not well understood at present. To help constrain galactic models, numerous precise abundances are necessary for a large range evolutionary stages, metallicities, Galactic volume. Aims. In age parametrization on industrial scales, spectroscopic surveys such APOGEE, GALAH, RAVE,...
The eighteenth data release of the Sloan Digital Sky Surveys (SDSS) is first one for SDSS-V, fifth generation survey. SDSS-V comprises three primary scientific programs, or "Mappers": Milky Way Mapper (MWM), Black Hole (BHM), and Local Volume (LVM). This contains extensive targeting information two multi-object spectroscopy programs (MWM BHM), including input catalogs selection functions their numerous objectives. We describe production databases calibration- scientifically-focused...
JWST has recently detected numerous disc galaxies at high-redshifts and there have been observations of cold z > 4 with ALMA. In the Milky Way, recent studies find metal-poor stars in orbits, suggesting an ancient disc. We investigated a sample 565,606 from hybrid-CNN analysis Gaia-DR3 RVS stars. The contains 8,500 [Fe/H]<-1. For subset ~200,000 main sequence turnoff subgiant we computed distances ages using StarHorse code mean precision 1% 12%, respectively. First, confirm existence thin...
(Abridged) Recent spectroscopic surveys have begun to explore the Galactic disk system outside solar neighborhood on basis of large data samples. In this way, they provide valuable information for testing spatial and temporal variations structure kinematics chemical evolution. We used a Gaussian mixture model algorithm, as rigurous mathematical approach, separate in [Mg/Fe] vs. [Fe/H] plane clean star subsample from Gaia-ESO survey internal release 2. find that sample is separated into five...