J/A+A/685/A59ivo://CDS.VizieR/J/A+A/685/A59doi:10.26093/cds/vizier.36850059CDSMatsuno T.Starkenburg E.Balbinot E.Helmi A.2024-11-29T20:02:31Z2024-05-06T08:51:36ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frchemically-peculiar-starsmetallicityline-intensitiesIn the latest Gaia data release (DR3), the GSP-Spec module has provided stellar parameters and chemical abundances measured from the RVS spectra alone. However, the GSP-Spec parameters, including metallicity, for very metal-poor stars (VMP stars; [Fe/H}]<-2) suffer from parameter degeneracy due to a lack of information in their spectra, and hence have large measurement uncertainty and systematic offset. We aim to provide more precise metallicity estimates for VMP stars analysed by the GSP-Spec module by taking photometric information into account in the analysis and breaking the degeneracy. We reanalyzed FGK type stars in the GSP-Spec catalog by computing the Ca triplet equivalent widths from the published set of GSP-Spec stellar parameters. We compare these recovered equivalent widths with the values directly measured from public Gaia RVS spectra and investigate the precision of the recovered values and the parameter range in which the recovered values are reliable. We then convert the recovered equivalent widths to metallicities adopting photometric temperatures and surface gravities that we derive based on Gaia and 2MASS catalogs. The recovered equivalent widths agree with the directly measured values with a scatter of 0.05dex for the stars that pass the GSP-Spec quality cuts. Among stars that were recommended to filter out, we observed a similar scatter for FGK-type stars initially misidentified as hot stars. Contrarily, we found a poorer agreement in general for stars that the GSP-Spec identified as cool K and M-type giants, although we can still define subsets that show reasonable agreement. At the low metallicity end ([Fe/H]<-1.5), our metallicity estimates have a typical uncertainty of 0.18dex, which is about half of the quoted GSP-Spec metallicity uncertainty at the same metallicity. Our metallicities also show better agreement with the high-resolution literature values than the original GSP-Spec metallicities at low metallicity; the scatter in the comparison decreases from 0.36-0.46dex to 0.17-0.29dex for stars that satisfy the GSP-Spec quality cuts. While the GSP-Spec metallicities show increasing scatter when misidentified "hot" stars and the subsets of the "cool K and M-type giants" are included (up to 1.06dex), we can now identify them as FGK-type stars and provide metallicities that show a small scatter in the comparisons (up to 0.34dex), which helps us to increase the number of VMP stars with reliable and precise metallicity. The inclusion of photometric information greatly contributes to breaking parameter degeneracy, enabling precise metallicity estimates for VMP stars from Gaia RVS spectra. We produce a publicly-available catalog of bright metal-poor stars suitable for high-resolution follow-up. The sample contains about 2345 VMP stars with an estimated contamination rate of 5%.2024A&A...685A..59Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/685/A59CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/685/A59https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/685/A59http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/685/A59https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/685/A59https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/685/A59http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/685/A59GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/685/A59/catalog (The catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/685/A59/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/685/A59/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/685/A59/catalog?GETtext/xml+votable180.050000true266.9886891599-34.02139008360.0055555555555555560/0-11 6/https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/685/A59?format=asciidefaultJ/A+A/685/A59/catalogThe catalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGaiaDR3Gaia DR3 source_idmeta.id;meta.mainRA_ICRSGaia DR3 right ascension (ICRS) at Ep=2016.0degpos.eq.ra;meta.mainindexedDE_ICRSGaia DR3 declination (ICRS) at Ep=2016.0degpos.eq.dec;meta.mainindexedTeffEffective temperature adopted in this workKphys.temperature.effectivefloatloggSurface gravity adopted in this worklog(cm.s**-2)phys.gravityfloat[Fe/H]Metallicity derived in this worklog(Sun)phys.abund.Zfloate_[Fe/H]Metallicity uncertainty derived in this worklog(Sun)stat.error;phys.abund.Fefloatlog(EW8498)Inferred equivalent width for the 8498{AA} linelog(0.1nm)spect.line.eqWidthfloatlog(EW8542)? Inferred equivalent width for the 8542{AA} linelog(0.1nm)spect.line.eqWidthfloatnullablelog(EW8662)? Inferred equivalent width for the 8662{AA} linelog(0.1nm)spect.line.eqWidthfloatnullableMPp[0/1] MP+ flag defined in the paper (1)meta.codeintRMP[0/1] RMP flag defined in the paper (2)meta.codeinteRMP1[0/1] eRMP1 flag defined in the paper (3)meta.codeinteRMP2[0/1] eRMP2 flag defined in the paper (4)meta.codeintRefPhotPhotometry used for the luminositymeta.bibcharE(B-V)E(B-V) on the SFD scalemagphot.color.excessfloatr_E(B-V)Source of E(B-V) (5)meta.ref;pos.framecharr_TeffColor used to derive Teffmeta.ref;pos.framechar