A5026477199- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Scientific Research and Discoveries
- Galaxies: Formation, Evolution, Phenomena
- Geophysics and Gravity Measurements
- Geomagnetism and Paleomagnetism Studies
- Cosmology and Gravitation Theories
- Astronomical and nuclear sciences
- Earth Systems and Cosmic Evolution
- Astrophysical Phenomena and Observations
- Remote Sensing in Agriculture
- Planetary Science and Exploration
- Traditional Chinese Medicine Studies
- Material Properties and Failure Mechanisms
- Geology and Paleoclimatology Research
- Industrial Engineering and Technologies
- Distributed and Parallel Computing Systems
- Engineering Diagnostics and Reliability
- Complex Systems and Time Series Analysis
European Space Astronomy Centre
2016-2022
Universitat de Barcelona
2014-2022
Osservatorio Astrofisico di Torino
2018-2021
Institut de Ciències del Cosmos
2017-2021
Institut Català de Ciències del Clima
2017-2021
Max Planck Society
2018
Universidad de Granada
2017
Before the publication of Gaia Catalogue, contents first data release have undergone multiple dedicated validation tests. These tests aim at analysing in-depth Catalogue content to detect anomalies, individual problems in specific objects or overall statistical properties, either filter them before public release, describe different caveats for an optimal exploitation data. Dedicated methods using internal data, external catalogues models been developed processes. They are testing normal...
We compare the Gaia DR2 and EDR3 performances in study of Magellanic Clouds show clear improvements precision accuracy new release. also that systematics still present data make determination 3D geometry LMC a difficult endeavour; this is at very limit usefulness astrometry, but it may become feasible with use additional external data. derive radial tangential velocity maps global profiles for several subsamples we defined. To our knowledge, first time two planar components ordered random...
We use Gaia DR2 magnitudes, colours and parallaxes for stars with G<12 to explore a 15-dimensional space that includes simultaneously the initial mass function (IMF) non-parametric star formation history (SFH) Galactic disc. This inference is performed by combining Besancon Galaxy Model fast approximate simulations (BGM FASt) an Bayesian computation algorithm. find in data imprint of burst 2-3 Gyr ago, thin disc domain, present rate (SFR) about 1 Msun. Our results show decreasing trend SFR...
The third gaia data release (DR3) provides a wealth of new products. early part the release, Gaia EDR3, already provided astrometric and photometric for nearly two billion sources. full now adds improved parameters compared to DR2 radial velocities, astrophysical parameters, variability information, light curves, orbits Solar System objects. improvements are in terms number sources, variety parameter precision, accuracy. For first time, DR3 also sample spectrophotometry spectra obtained with...
Context. Accurate astrometry achieved by Gaia for many stars in the Milky Way provides an opportunity to reanalyse Galactic stellar populations from a large and homogeneous sample revisit Galaxy gravitational potential. Aims. This paper shows how self-consistent dynamical model can be obtained fitting potential of kinematics densities data. Methods. We derived using Besancon Model, computed disc distribution functions based on three integrals motion ( E , L z I 3 ) stationary discs. The are...
Abstract The era of all-sky space astrometry began with the Hipparcos mission in 1989 and provided first very accurate catalogue apparent magnitudes, positions, parallaxes proper motions 120 000 bright stars at milliarcsec (or per year) accuracy level. has now been superseded by results Gaia mission. second data release contained astrometric for almost 1.7 billion sources tens microarcsec a vast volume Milky Way future releases will further improve on this. just completed its nominal 5-year...
We investigate the properties of double sequences Milky Way discs visible in [$\alpha$/Fe] vs [Fe/H] diagram. In framework Galactic formation and evolution, we discuss complex relationships between age, metallicity, [$\alpha$/Fe], velocity components. study stars with measured chemical, seismic astrometric from APOGEE survey, Kepler Gaia satellites, respectively. separate [$\alpha$/Fe]-[Fe/H] diagram into 3 stellar populations: thin disc, high-$\alpha$ metal-poor thick disc metal-rich...
We develop a new theoretical framework to generate Besan\c{c}on Galaxy Model fast approximate simulations (BGM FASt) address fundamental questions of the Galactic structure and evolution performing multi-parameter inference. As first application our strategy we simultaneously infer IMF, star formation history stellar mass density in Solar Neighbourhood. The BGM FASt is based on reweighing scheme, that uses specific pre-sampled simulation, assumption distribution function generated stars can...
Context: The Initial Mass Function (IMF) plays a crucial role on galaxy evolution and its implications star formation theory make it milestone for the next decade. It is in intermediate high mass ranges where uncertainties of IMF are larger. This major subject debate analysis both Galactic extragalactic science. Aims: Our goal to constrain thin disc population using Classical Cepheids Tycho-2 data. Methods: For first time Besançon Galaxy Model (BGM) has been used characterise Cepheids. We...
Extensive surveys of star-forming regions with Spitzer have revealed populations disk-bearing young stellar objects. These provided crucial constraints, such as the timescale dispersal protoplanetary disks, obtained by carefully combining infrared data spectroscopic or X-ray data. While observations in various agree general trend decreasing disk fraction age, Lupus V and VI appeared to been at odds, having an extremely low fraction. Here we show, using recent Gaia release 2 (DR2), that these...
We use the Gaia-TGAS data to compare transverse velocities in Galactic longitude (coming from proper motions and parallaxes) Milky Way disk for negative positive longitudes as a function of distance. The are strongly asymmetric deviate significantly expectations an axisymmetric Galaxy. value sign asymmetry changes at spatial scales several tens degrees about 0.5 kpc is statistically significant 95% confidence level 57% region probed, which extends up ~1.2 kpc. A percentage 24% studied shows...
SN 1572 (Tycho Brahe's supernova) clearly belongs to the Ia (thermonuclear) type. It was produced by explosion of a white dwarf in binary system. Its remnant has been first this type be explored search possible surviving companion, mass donor that brought point explosion. A high peculiar motion with respect stars at same location Galaxy, mainly due orbital velocity time explosion, is basic criterion for detection such companions. Radial velocities from spectra close geometrical center...
Here, we consider a (m, ni) order system having 'm' number of subsystems connected in series and each subsystem has 'n' components parallel. The reliability the been obtained by deleting 'y' (or adding 'x' subsystems) from to) it. variation due to alteration assessed for particular (4,3) order. A regression approach is used quantify strength subsystems. coefficient determination (R2) adjusted R2 are also examine goodness fit. shown numerically graphically value parameters. application...
Abstract Cepheids are excellent stellar tracers: they bright enough to be observed even at large distances; their distances can accurately determined via period-luminosity relations; spectra contain numerous lines that enable us derive abundances for many α, iron-peak or neutron-capture elements. Classical yellow supergiants trace the young populations (⩽ 300 Myr); Type II post Horizontal Branch, low-mass, Population stars (⩾ 10 Gyr). Both used purposes in Milky Way archaeology.
Aims. To constrain the Initial Mass Function (IMF) of Galactic young (<1 Gyr) thin Disc population using Cepheids.