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Chemical abundances in the ancient Milky Way: G-type SDSS stars. Automated determination of T_{eff}, log g, [Fe/H] and [alpha /F]

hal.structure.identifierLaboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
hal.structure.identifierObservatoire aquitain des sciences de l'univers [OASU]
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
dc.contributor.authorGIRARD, Pascal
dc.contributor.authorALLENDE PRIETO, C.
hal.structure.identifierLaboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
hal.structure.identifierObservatoire aquitain des sciences de l'univers [OASU]
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
dc.contributor.authorSOUBIRAN, C.
dc.date.issued2006
dc.identifier.issn0037-8720
dc.description.abstractEnWe have developed TGMETalpha in order to determine T_{eff}, log g, [Fe/H] and [alpha /Fe] for large samples of FGK stars observed at various spectral resolutions. Tests on several hundred echelle spectra of reference stars degraded to low resolution (R=1.000) indicate typical rms precisions of sigma (T_{eff})˜150 K, sigma (logg)˜0.44, sigma ([Fe/H])˜0.15 and sigma ([alpha /Fe])˜0.06. We have used TGMETalpha to determine atmospheric parameters and alpha -abundances from ˜15000 SDSS stellar spectra. Thanks to this very large sample we have investigated the vertical, radial and rotational properties as well as the abundance ratio of alpha elements to iron, [alpha /Fe], of samples representative of the thick disk and the halo. Results presented in the poster, provide new constraints on galactic thick disk formation models. We find evidence for a strong negative radial gradient in [alpha /Fe] with a lack or small one in [Fe/H] in the thick disk. Moreover, there is a lack of vertical gradient in both [Fe/H] and [alpha /Fe]. These features have to be reconciled with the timescale of the thick disk formation as well as with the SFR, IMF, infall of gas or accreted satellite debris.
dc.language.isoen
dc.publisherSocietà astronomica italiana
dc.subject.enThick Disk
dc.subject.enStars: Galactic Halo
dc.subject.enStars: fundamental parameters
dc.subject.enabundances
dc.subject.enGalaxy: structure
dc.subject.enGalaxy: stellar content
dc.title.enChemical abundances in the ancient Milky Way: G-type SDSS stars. Automated determination of T_{eff}, log g, [Fe/H] and [alpha /F]
dc.typeArticle de revue
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Cosmologie et astrophysique extra-galactique [astro-ph.CO]
dc.subject.halPlanète et Univers [physics]/Astrophysique [astro-ph]
bordeaux.journalMemorie della Societa astronomica italiana
bordeaux.page1173
bordeaux.volume77
bordeaux.peerReviewedoui
hal.identifierhal-00130080
hal.version1
hal.popularnon
hal.audienceNon spécifiée
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-00130080v1
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