G. Contursi
A5079651580- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Scientific Research and Discoveries
- Geophysics and Gravity Measurements
- Astronomical Observations and Instrumentation
- Geomagnetism and Paleomagnetism Studies
- Galaxies: Formation, Evolution, Phenomena
- Planetary Science and Exploration
- Atmospheric Ozone and Climate
- Remote Sensing in Agriculture
- Distributed and Parallel Computing Systems
- Complex Systems and Time Series Analysis
- Solar Radiation and Photovoltaics
- History and Developments in Astronomy
- Earth Systems and Cosmic Evolution
- Cosmology and Gravitation Theories
- Solar and Space Plasma Dynamics
- Astronomical and nuclear sciences
- Adaptive optics and wavefront sensing
Observatoire de la Côte d’Azur
2020-2023
Université Côte d'Azur
2020-2023
Centre National de la Recherche Scientifique
2020-2023
Lagrange Laboratory
2020-2022
The chemo-physical parametrisation of stellar spectra is essential for understanding the nature and evolution stars Galactic populations. Gaia DR3 contains RVS data performed by General Stellar Parametriser-spectroscopy, module. Here we describe first 34 months observations. GSP-spec estimates parameters from combined single stars. main analysis workflow described here, MatisseGauguin, based on projection optimisation methods provides atmospheric parameters; individual chemical abundances N,...
Gaia Data Release 3 contains a wealth of new data products for the community. Astrophysical parameters are major component this release. They were produced by inference system (Apsis) within Processing and Analysis Consortium. The aim paper is to describe overall content astrophysical in how they produced. In Apsis we use mean BP/RP RVS spectra along with astrometry photometry, derive following parameters: source classification probabilities 1.6 billion objects, interstellar medium...
We present the General Stellar Parameterizer from Photometry (GSP-Phot), which is part of astrophysical parameters inference system (Apsis). GSP-Phot designed to produce a homogeneous catalogue for hundreds millions single non-variable stars based on their astrometry, photometry, and low-resolution BP/RP spectra. These are effective temperature, surface gravity, metallicity, absolute $M_G$ magnitude, radius, distance, extinction each star. uses Bayesian forward-modelling approach...
Gaia Data Release 3 contains a wealth of new data products for the community. Astrophysical parameters are major component this release. They were produced by inference system (Apsis) within Processing and Analysis Consortium. The aim paper is to describe overall content astrophysical in how they produced. In Apsis we use mean BP/RP RVS spectra along with astrometry photometry, derive following parameters: source classification probabilities 1.6 billion objects, interstellar medium...
Context. As part of the third Gaia data release, we present contributions non-stellar and classification modules from eighth coordination unit (CU8) Data Processing Analysis Consortium, which is responsible for determination source astrophysical parameters using data. This in a series three papers describing work done within CU8 this release. Aims. For each five relevant CU8, summarise their objectives, methods they employ, performance, results produce DR3. We further advise how to use these...
Context. The recent Gaia Data Release 3 (DR3) represents an unparalleled revolution in Galactic archaeology, providing numerous radial velocities and chemical abundances for millions of stars as well all-sky coverage. Aims We present a new evolution model the disc components (high- low- α sequence stars) designed to reproduce abundance ratios provided by General Stellar Parametriser-spectroscopy module DR3 constrained detailed star formation (SF) histories both thick thin inferred from...
The recent Gaia Third Data Release contains a homogeneous analysis of millions high-quality Radial Velocity Spectrometer (RVS) stellar spectra by the GSP-Spec module. This led to estimation individual chemical abundances and allows us chemically map Milky Way. Among published abundances, three heavy-elements produced neutron-captures in interiors can be found: Ce, Zr Nd. We use sample about 30,000 LTE Ce selected after applying different combinations flags. Thanks DR3 astrometric data radial...
The Gaia mission is a magnitude-limited whole-sky survey that collects an impressive quantity of astrometric, spectro-photometric and spectroscopic data. Among all the on-board instruments, Radial Velocity Spectrometer (RVS) produces millions spectra up to magnitude G$_{RVS} \sim 16$. For brightest RVS targets, stellar atmospheric parameters individual chemical abundances are automatically estimated by Generalized Stellar Parametriser - spectroscopy group (GSP-Spec). These data will be...
The Gaia Radial Velocity Spectrometer provides the unique opportunity of a spectroscopic analysis millions stars at medium-resolution in near-infrared. This wavelength range includes Ca II infrared triplet (IRT), which is good diagnostics magnetic activity chromosphere late-type stars. Here we present method devised for inferring stellar index together with its scientific validation. A sample well studied PMS considered to identify regime may be affected by mass accretion. position these...
Aims. In this work we use the Gaia DR3 set of ultracool dwarf candidates and complement spectrophotometry with additional photometry in order to characterise its global properties. This includes inference distances, their locus colour-absolute magnitude diagram (biased through selection) luminosity function faint end Main Sequence. We study overall changes RP spectra as a spectral type. UCDs binary systems, attempt identify low-mass members nearby young associations, star forming regions...
Studies of the correlation between different diffuse interstellar bands (DIBs) are important for exploring their origins. However, Gaia-RVS spectral window 846 and 870 nm contains few DIBs, strong DIB at 862 being only convincingly confirmed one. Here we attempt to confirm existence a broad around 864.8 estimate its characteristics using stacked spectra large number stars. We study correlations two DIBs nm, as well extinction. obtained medium absorption by subtracting stellar components...
The recent parameterisation by the GSP-spec module of Gaia/RVS spectra has produced an homogeneous catalogue about 174,000 AGB stars. Among 13 chemical elements presented in this catalogue, abundance 2 them (Ce and Nd) have been estimated most these AGBs. These species formed slow n-captures interior low- intermediate-mass stars, belong to family 2nd-peak s-process elements. We defined a working sample 19,544 stars with high-quality Ce and/or Nd abundances, selected applying specific...
Context. The chemical evolution of neutron capture elements in the Milky Way is still a matter debate. Although more and studies investigate their behaviour, there lack significant large sample abundances key heavy element: lead. Aims. Lead final product s-process nucleosynthesis channel one most stable elements. goal this article to present largest catalogue homogeneous Pb abundances, particular for metallicities higher than −1.0 dex, then study lead content Way. Methods. We analysed...
Context. The recent parameterisation by the GSP-Spec module of Gaia /Radial Velocity Spectrometer stellar spectra has produced an homogeneous catalogue about 174 000 asymptotic giant branch (AGB) stars. Among 13 chemical elements presented in this third data release, abundance two them (cerium and neodymium) have been estimated most these AGB These species are formed slow neutron captures ( s -process) interior low- intermediate-mass They belong to family second-peak -process elements. Aims....
Context. The contribution of quiet-Sun regions to the solar irradiance variability is currently unclear. Certain solar-cycle variations quiet-Sun’s physical structure, such as temperature gradient, might affect irradiance. Accurate measurements this quantity over course activity cycle would improve our understanding long-term variations. Aims. In a previous work, we introduced and successfully tested new spectroscopic method for measuring photospheric gradient directly on geometric scale in...
Studies of the correlation between different diffuse interstellar bands (DIBs) are important for exploring their origins. However, Gaia-RVS spectral window 846 and 870 nm contains few DIBs, strong DIB at 862 being only convincingly confirmed one. Here we attempt to confirm existence a broad around 864.8 estimate its characteristics using stacked spectra large number stars. We study correlations two DIBs nm, as well extinction. obtained medium absorption by subtracting stellar components...