Examinando por Autor "Babusiaux C."
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Ítem Gaia focused product release : asteroid orbital solution: properties and assessmen(EDP Sciences, 2023-12) David P.; Mignard F.; Hestroffer D.; Tanga P.; Spoto F.; Berthier J.; Pauwels T.; Roux W.; Barbier A.; Cellino A.; Carry B.; Delbo M.; Dell'oro A.; Fouron C.; Galluccio L.; Klioner S.A.; Mary N.; Muinonen K.; Ordenovic C.; Oreshina-Slezak I.; Panem C.; Petit J.-M.; Portell J.; Brown A.G.A; Thuillot W.; Vallenari A.; Prusti T.; De Bruijne J.H.J.; Arenou F.; Babusiaux C.; Biermann M.; Creevey O.L.; Ducourant C.; Evans D.W.; Eyer L.; Guerra R.; Hutton A.; Jordi C.; Lammers U.; Lindegren L.; Luri X.; Randich S.; Sartoretti P.; Smiljanic R.; Walton N.A.; Bailer-Jones C.A.L.; Bastian U.; Cropper M.; Drimmel R.; Katz D.; Soubiran C.; Van Leeuwen F.; Audard M.; Bakker J.; Blomme R.; Castañeda J.; De Angeli F.; Fabricius C.; Fouesneau M; Frémat Y.; Guerrier A.; Masana E.; Messineo R.; Nicolas C.; Nienartowicz K.; Pailler F.; Panuzzo P.; Riclet F.; Seabroke G.M.; Sordo R.; Thévenin F.; Gracia-Abril G.; Teyssier D.; Altmann M.; Benson K.; Burgess P.W.; Busonero D.; Busso G.; Cánovas H.; Cheek N.; Clementini G.; Damerdji Y.; Davidson M.; De Teodoro P.; Delchambre L.; Fraile Garcia E.; Garabato D.; García-Lario P.; Garralda Torres N.; Gavras P.; Haigron R.; Hambly N.C.; Harrison D.L.; Hatzidimitriou D.; Hernández J.; Hodgkin S.T.; Holl B.; Jamal S.; Jordan S.; Krone-Martins A.; Lanzafame A.C.; Löffler W.; Lorca A.; Marchal O.; Marrese P.M.; Moitinho A.; Nuñez Campos M.; Osborne P.; Pancino E.; Recio-Blanco A.; Riello M.; Rimoldini L.; Robin A.C.; Roegiers T.; Sarro L.M.; Schultheis M.; Siopis C.; Smith M.; Sozzetti A.; Utrilla E.; Van Leeuwen M.; Weingrill K.; Abbas U.; Ábrahám P.; Abreu Aramburu A.; Aerts C.; Altavilla G.; Álvarez M.A.; Alves J.; Anderson R.I.; Antoja T.; Baines D.; Baker S.G.; Balog Z.; Barache C.; Barbato D.; Barros M.; Barstow M.A.; Bartolomé S.; Bashi D.; Bauchet N.; Baudeau N.; Becciani U.; Bedin L.R.; Bellas-Velidis I.; Bellazzini M.; Beordo W.; Berihuete A.; Bernet M.; Bertolotto C.; Bertone S.; Bianchi L.; Binnenfeld A.; Blazere A.; Boch T.; Bombrun A.; Bouquillon S.; Bragaglia A.; Braine J.; Bramante L.; Breedt E.; Bressan A.; Brouillet N.; Brugaletta E.; Bucciarelli B.; Butkevich A.G.; Buzzi R.; Caffau E.; Cancelliere R.; Cannizzo S.; Carballo R.; Carlucci T.; Carnerero M.I.; Carrasco J.M.; Carretero J.; Carton S.; Casamiquela L.; Castellani M.; Castro-Ginard A.; Cesare V.; Charlot P.; Chemin L.; Chiaramida V.; Chiavassa A.; Chornay N.; Collins R.; Contursi G.; Cooper W.J.; Cornez T.; Crosta M.; Crowley C.; Dafonte C.; De Laverny P.; De Luise F.; De March R.; De Souza R.; De Torres A.; Del Peloso E.F.; Delgado A.; Dharmawardena T.E.; Diakite S.; Diener C.; Distefano E.; Dolding C.; Dsilva K.; Durán J.; Enke H.; Esquej P.; Fabre C.; Fabrizio M.; Faigler S.; Fatović M.; Fedorets G.; Fernández-Hernández J.; Fernique P.; Figueras F.; Fournier Y.; Gai M.; Galinier M.; Garcia-Gutierrez A.; García-Torres M.; Garofalo A.; Gerlach E; Geyer R.; Giacobbe P.; Gilmore G.; Girona S.; Giuffrida G.; Gomel R.; Gomez A.; González-Núñez J.; González-Santamaría I.; Gosset E.; Granvik M.; Gregori Barrera V.; Gutiérrez-Sánchez R.; Haywood M.; Helmer A.; Helmi A.; Henares K.; Hidalgo S.L.; Hilger T.; Hobbs D.; Hottier C.; Huckle H.E.; Jabłońska M.; Jansen F.; Jiménez-Arranz Ó.; Juaristi Campillo J.; Khanna S.; Kordopatis G.; Kóspál Á.; Kostrzewa-Rutkowska Z.; Kun M.; Lambert S.; Lanza A.F.; Le Campion J.-F.; Lebreton Y.; Lebzelter T.; Leccia S.; Lecoeur-Taibi I.; Lecoutre G.; Liao S.; Liberato L.; Licata E.; Lindstrøm H.E.P.; Lister T.A.; Livanou E.; Lobel A.; Loup C.; Mahy L.; Mann R.G.; Manteiga M.; Marchant J.M.; Marconi M.; Marín Pina D.; Marinoni S.; Marshall D.J.; Martín Lozano J.; Martín-Fleitas J.M.; Marton G.; Masip A.; Massari D.; Mastrobuono-Battisti A.; Mazeh T.; McMillan P.J.; Meichsner J.; Messina S.; Michalik D.; Millar N.R.; Mints A.; Molina D.; Molinaro R.; Molnár L.; Monari G.; Monguió M.; Montegriffo P.; Montero A.; Mor R.; Mora A.; Morbidelli R.; Morel T.; Morris D.; Mowlavi N.; Munoz D.; Muraveva T.; Murphy C.P.; Musella I.; Nagy Z.; Nieto S.; Noval L.; Ogden A.; Pagani C.; Pagano I.; Palaversa L.; Palicio P.A.; Pallas-Quintela L.; Panahi A.; Payne-Wardenaar S.; Pegoraro L.; Penttilä A.; Pesciullesi P.; Piersimoni A.M.; Pinamonti M.; Pineau F.-X.; Plachy E.; Plum G.; Poggio E.; Pourbaix D.; Prša A.; Pulone L.; Racero E.; Rainer M.; Raiteri C.M.; Ramos P.; Ramos-Lerate M.; Ratajczak M.; Re Fiorentin P.; Regibo S.; Reylé C.; Ripepi V.; Riva A.; Rix H.-W.; Rixon G.; Robichon N.; Robin C.; Romero-Gómez M.; Rowell N.; Royer F.; Ruz Mieres D.; Rybicki K.A.; Sadowski G.; Sáez Núñez A.; Sagristà Sellés A.; Sahlmann J.; Sanchez Gimenez V.; Sanna N.; Santoveña R.; Sarasso M.; Sarrate Riera C.; Sciacca E.; Segovia J.C.; Ségransan D.; Shahaf S.; Siebert A.; Siltala L.; Slezak E.; Smart R.L.; Snaith O.N.; Solano E.; Solitro F.; Souami D.; Souchay J.; Spina L.; Spitoni E.; Squillante L.A.; Steele I.A.; Steidelmüller H.; Surdej J.; Szabados L.; Taris F.; Taylor M.B.; Teixeira R.; Tisanić K.; Tolomei L.; Torra F.; Torralba Elipe G.; Trabucchi M.; Tsantaki M.; Ulla A.; Unger N.; Vanel O.; Vecchiato A.; Vicente D.; Voutsinas S.; Weiler M.; Wyrzykowski Ł.; Zhao H.; Zorec J.; Zwitter T.; Balaguer-Núñez L.; Leclerc N.; Morgenthaler S.; Robert G.; Zucker S.Context. We report the exploitation of a sample of Solar System observations based on data from the third Gaia Data Release (Gaia DR3) of nearly 157 000 asteroids. It extends the epoch astrometric solution over the time coverage planned for the Gaia DR4, which is not expected before the end of 2025. This data set covers more than one full orbital period for the vast majority of these asteroids. The orbital solutions are derived from the Gaia data alone over a relatively short arc compared to the observation history of many of these asteroids. Aims. The work aims to produce orbital elements for a large set of asteroids based on 66 months of accurate astrometry provided by Gaia and to assess the accuracy of these orbital solutions with a comparison to the best available orbits derived from independent observations. A second validation is performed with accurate occultation timings. Methods. We processed the raw astrometric measurements of Gaia to obtain astrometric positions of moving objects with 1D sub-mas accuracy at the bright end. For each asteroid that we matched to the data, an orbit fitting was attempted in the form of the best fit of the initial conditions at the median epoch. The force model included Newtonian and relativistic accelerations to derive the observation equations, which were solved with a linear least-squares fit. Results. Orbits are provided in the form of state vectors in the International Celestial Reference Frame for 156 764 asteroids, including near-Earth objects, main-belt asteroids, and Trojans. For the asteroids with the best observations, the (formal) relative uncertainty σa/a is better than 10-10. Results are compared to orbits available from the Jet Propulsion Laboratory and MPC. Their orbits are based on much longer data arcs, but from positions of lower quality. The relative differences in semi-major axes have a mean of 5 × 10-10 and a scatter of 5 × 10-9 © The Authors 2023.Ítem The gaia -ESO survey: Calibration strategy(EDP Sciences, 2017-02) Pancino E.; Lardo C.; Altavilla G.; Marinoni S.; Ragaini S.; Cocozza G.; Bellazzini M.; Sabbi E.; Zoccali M.; Donati P.; Heiter U.; Koposov S.E.; Blomme R.; Morel T.; Símon-Díaz S.; Lobel A.; Soubiran C.; Montalban J.; Valentini M.; Casey A.R.; Blanco-Cuaresma S.; Jofré P.; Worley C.C.; Magrini L.; Hourihane A.; François P.; Feltzing S.; Gilmore G.; Randich S.; Asplund M.; Bonifacio P.; Drew J.E.; Jeffries R.D.; Micela G.; Vallenari A.; Alfaro E.J.; Allende Prieto C.; Babusiaux C.; Bensby T.; Bragaglia A.; Flaccomio E.; Hambly N.; Korn A.J.; Lanzafame A.C.; Smiljanic R.; Van Eck S.; Walton N.A.; Bayo A.; Carraro G.; Costado M.T.; Damiani F.; Edvardsson B.; Franciosini E.; Frasca A.; Lewis J.; Monaco L.; Morbidelli L.; Prisinzano L.; Sacco G.G.; Sbordone L.The Gaia-ESO survey (GES) is now in its fifth and last year of observations and has produced tens of thousands of high-quality spectra of stars in all Milky Way components. This paper presents the strategy behind the selection of astrophysical calibration targets, ensuring that all GES results on radial velocities, atmospheric parameters, and chemical abundance ratios will be both internally consistent and easily comparable with other literature results, especially from other large spectroscopic surveys and from Gaia. The calibration of GES is particularly delicate because of (i) the large space of parameters covered by its targets, ranging from dwarfs to giants, from O to M stars; these targets have a large wide of metallicities and also include fast rotators, emission line objects, and stars affected by veiling; (ii) the variety of observing setups, with different wavelength ranges and resolution; and (iii) the choice of analyzing the data with many different state-of-the-art methods, each stronger in a different region of the parameter space, which ensures a better understanding of systematic uncertainties. An overview of the GES calibration and homogenization strategy is also given, along with some examples of the usage and results of calibrators in GES iDR4, which is the fourth internal GES data release and will form the basis of the next GES public data release. The agreement between GES iDR4 recommended values and reference values for the calibrating objects are very satisfactory. The average offsets and spreads are generally compatible with the GES measurement errors, which in iDR4 data already meet the requirements set by the main GES scientific goals. © ESO, 2017.Ítem The Gaia -ESO Survey: Exploring the complex nature and origins of the Galactic bulge populations(EDP Sciences, 2017-05) Rojas-Arriagada A.; Recio-Blanco A.; De Laverny P.; Mikolaitis Š.; Matteucci F.; Spitoni E.; Schultheis M.; Hayden M.; Hill V.; Zoccali M.; Minniti D.; Gonzalez O.A.; Gilmore G.; Randich S.; Feltzing S.; Alfaro E.J.; Babusiaux C.; Bensby T.; Bragaglia A.; Flaccomio E.; Koposov S.E.; Pancino E.; Bayo A.; Carraro G.; Casey A.R.; Costado M.T.; Damiani F.; Donati P.; Franciosini E.; Hourihane A.; Jofré P.; Lardo C.; Lewis J.; Lind K.; Magrini L.; Morbidelli L.; Sacco G.G.; Worley C.C.; Zaggia S.Context. As observational evidence steadily accumulates, the nature of the Galactic bulge has proven to be rather complex: the structural, kinematic, and chemical analyses often lead to contradictory conclusions. The nature of the metal-rich bulge - and especially of the metal-poor bulge - and their relation with other Galactic components, still need to be firmly defined on the basis of statistically significant high-quality data samples. Aims. We used the fourth internal data release of the Gaia-ESO survey to characterize the bulge metallicity distribution function (MDF), magnesium abundance, spatial distribution, and correlation of these properties with kinematics. Moreover, the homogeneous sampling of the different Galactic populations provided by the Gaia-ESO survey allowed us to perform a comparison between the bulge, thin disk, and thick disk sequences in the [Mg/Fe] vs. [Fe/H] plane in order to constrain the extent of their eventual chemical similarities. Methods. We obtained spectroscopic data for ∼2500 red clump stars in 11 bulge fields, sampling the area -10° ≥ l ≥ +8° and -10° ≥ b ≥ -4° from the fourth internal data release of the Gaia-ESO survey. A sample of ∼6300 disk stars was also selected for comparison. Spectrophotometric distances computed via isochrone fitting allowed us to define a sample of stars likely located in the bulge region. Results. From a Gaussian mixture models (GMM) analysis, the bulge MDF is confirmed to be bimodal across the whole sampled area. The relative ratio between the two modes of the MDF changes as a function of b, with metal-poor stars dominating at high latitudes. The metal-rich stars exhibit bar-like kinematics and display a bimodality in their magnitude distribution, a feature which is tightly associated with the X-shape bulge. They overlap with the metal-rich end of the thin disk sequence in the [Mg/Fe] vs. [Fe/H] plane. On the other hand, metal-poor bulge stars have a more isotropic hot kinematics and do not participate in the X-shape bulge. Their Mg enhancement level and general shape in the [Mg/Fe] vs. [Fe/H] plane is comparable to that of the thick disk sequence. The position at which [Mg/Fe] starts to decrease with [Fe/H], called the "knee", is observed in the metal-poor bulge at [Fe/H]knee = -0:37 ± 0:09, being 0.06 dex higher than that of the thick disk. Although this difference is inside the error bars, it suggest a higher star formation rate (SFR) for the bulge than for the thick disk. We estimate an upper limit for this difference of Δ[Fe/H]knee = 0:24 dex. Finally, we present a chemical evolution model that suitably fits the whole bulge sequence by assuming a fast (<1 Gyr) intense burst of stellar formation that takes place at early epochs. Conclusions.We associate metal-rich stars with the bar boxy/peanut bulge formed as the product of secular evolution of the early thin disk. On the other hand, the metal-poor subpopulation might be the product of an early prompt dissipative collapse dominated by massive stars. Nevertheless, our results do not allow us to firmly rule out the possibility that these stars come from the secular evolution of the early thick disk. This is the first time that an analysis of the bulge MDF and α-abundances has been performed in a large area on the basis of a homogeneous, fully spectroscopic analysis of high-resolution, high S/N data. © ESO 2017.Ítem The Gaia-ESO Survey: Galactic evolution of sulphur and zinc(EDP Sciences, 2017-08) Duffau S.; Caffau E.; Babusiaux C.; Damiani F.; Franciosini E.; Jofré P.; Sbordone L.; Salvadori S.; Hourihane A.; Lardo C.; Lewis J.; Morbidelli L.; Sousa S.G.; Worley C.C.; Bonifacio P.; Andrievsky S.; Korotin S.; Monaco L.; François P.; Skúladóttir Á.; Bragaglia A.; Donati P.; Spina L.; Gallagher A.J.; Ludwig H.-G.; Christlieb N.; Hansen C.J.; Mott A.; Steffen M.; Zaggia S.; Blanco-Cuaresma S.; Calura F.; Friel E.; Jiménez-Esteban F.M.; Koch A.; Magrini L.; Pancino E.; Tang B.; Tautvaišiene G.; Vallenari A.; Hawkins K.; Gilmore G.; Randich S.; Feltzing S.; Bensby T.; Flaccomio E.; Smiljanic R.; Bayo A.; Carraro G.; Casey A.R.; Costado M.T.Context. Due to their volatile nature, when sulphur and zinc are observed in external galaxies, their determined abundances represent the gas-phase abundances in the interstellar medium. This implies that they can be used as tracers of the chemical enrichment of matter in the Universe at high redshift. Comparable observations in stars are more difficult and, until recently, plagued by small number statistics. Aims. We wish to exploit the Gaia-ESO Survey (GES) data to study the behaviour of sulphur and zinc abundances of a large number of Galactic stars, in a homogeneous way. Methods. By using the UVES spectra of the GES sample, we are able to assemble a sample of 1301 Galactic stars, including stars in open and globular clusters in which both sulphur and zinc were measured. Results. We confirm the results from the literature that sulphur behaves as an α-element. We find a large scatter in [Zn/Fe] ratios among giant stars around solar metallicity. The lower ratios are observed in giant stars at Galactocentric distances less than 7.5 kpc. No such effect is observed among dwarf stars, since they do not extend to that radius. Conclusions. Given the sample selection, giants and dwarfs are observed at different Galactic locations, and it is plausible, and compatible with simple calculations, that Zn-poor giants trace a younger population more polluted by SN Ia yields. It is necessary to extend observations in order to observe both giants and dwarfs at the same Galactic location. Further theoretical work on the evolution of zinc is also necessary. © 2017 ESO.Ítem The Gaia-ESO Survey: Low-α element stars in the Galactic bulge(EDP Sciences, 2017-07) Recio-Blanco A.; Rojas-Arriagada A.; De Laverny P.; Mikolaitis S.; Hill V.; Zoccali M.; Fernández-Trincado J.G.; Robin A.C.; Babusiaux C.; Gilmore G.; Randich S.; Alfaro E.; Allende Prieto C.; Bragaglia A.; Carraro G.; Jofré P.; Lardo C.; Monaco L.; Morbidelli L.; Zaggia S.We take advantage of the Gaia-ESO Survey iDR4 bulge data to search for abundance anomalies that could shed light on the composite nature of the Milky Way bulge. The α-element (Mg, Si, and whenever available, Ca) abundances, and their trends with Fe abundances have been analysed for a total of 776 bulge stars. In addition, the aluminum abundances and their ratio to Fe and Mg have also been examined. Our analysis reveals the existence of low-α element abundance stars with respect to the standard bulge sequence in the [α/ Fe] versus [Fe/H] plane. Eighteen objects present deviations in [α/ Fe] ranging from 2.1 to 5.3σ with respect to the median standard value. Those stars do not show Mg-Al anti-correlation patterns. Incidentally, this sign of the existence of multiple stellar populations is reported firmly for the first time for the bulge globular cluster NGC 6522. The identified low-α abundance stars have chemical patterns that are compatible with those of the thin disc. Their link with massive dwarf galaxies accretion seems unlikely, as larger deviations in α abundance and Al would be expected. The vision of a bulge composite nature and a complex formation process is reinforced by our results. The approach used, which is a multi-method and model-driven analysis of high resolution data, seems crucial to reveal this complexity. © ESO, 2017.