J/ApJ/810/76ivo://CDS.VizieR/J/ApJ/810/76doi:10.26093/cds/vizier.18100076CDSShort C.I.Young M.E.Layden N.2017-01-23T22:00:00Z2016-01-18T13:59:08ZCDS support team

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

cds-question@unistra.frchemical-abundancesgiant-starsastronomical-modelsWe investigate the dependence of the complete system of 22 Lick indices on overall metallicity scaled from solar abundances, [M/H], from the solar value, 0.0, down to the extremely metal-poor (XMP) value of -6.0, for late-type giant stars (MK luminosity class III, logg=2.0) of MK spectral class late-K to late-F (3750<Teff<6500K) of the type that are detected as "fossils" of early galaxy formation in the Galactic halo and in extra-galactic structures. Our investigation is based on synthetic index values, I, derived from atmospheric models and synthetic spectra computed with PHOENIX in Local Thermodynamic Equilibrium (LTE) and Non-LTE (NLTE), where the synthetic spectra have been convolved to the spectral resolution, R, of both IDS and SDSS (and LAMOST) spectroscopy. We identify nine indices, that we designate "Lick-XMP", that remain both detectable and significantly [M/H]-dependent down to [M/H] values of at least ~-5.0, and down to [M/H]~-6.0 in five cases, while also remaining well-behaved (single-valued as a function of [M/H] and positive in linear units). For these nine indices, we study the dependence of I on NLTE effects, and on spectral resolution. For our LTE I values for spectra of SDSS resolution, we present the fitted polynomial coefficients, C_n_, from multi-variate linear regression for I with terms up to third order in the independent variable pairs (Teff, [M/H]) and (V-K, [M/H]), and compare them to the fitted C_n_ values of Worthey et al. (1994, J/ApJS/94/687) at IDS spectral resolution.2015ApJ...810...76Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/810/76CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/MNRAS/435/3667 : Equivalent widths of 6 NGC5694 stars (Mucciarelli+, 2013)J/ApJ/778/56 : Hamburg/ESO Survey extremely metal-poor stars (Cohen+, 2013)J/MNRAS/429/126 : Atmospheric parameters from Fe lines (Ruchti+, 2013)J/AJ/145/13 : Metal-poor stars from SDSS/SEGUE I. Abundances (Aoki+, 2013)J/A+A/549/A129 : Equivalent widths of cool stars (Cesetti+, 2013)J/ApJ/751/156 : Ti and Fe lines in red supergiants (Bergemann+, 2012)J/ApJS/111/377 : H{gamma} + H{delta} absorption features (Worthey+ 1997)J/ApJS/94/687 : Old stellar populations. V. (Worthey+, 1994)J/AJ/103/1987 : Stars of very low metal abundance (Beers+ 1992)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/810/76https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/810/76http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/810/76https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/810/76https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/810/76http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/810/76GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/ApJ/810/76/table7LTE Partial I derivatives with respect to V-K and [M/H], at each grid value of V-K for [M/H]=0.0 models and [M/H], in index units and in units of {sigma} for SDSS spectral resolution for our nine H Lick-XMP indicesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintType[1/4] Partial derivative description (1)meta.codeintIndexLick-XMP index (Fe4383, Fe4531, Fe5015, Fe5270, Fe5335, Fe5406, Mg b, Mg_1_ and Na D)spect.indexcharZ[-6/-0] Model metallicityphys.abund.Z;meta.modelledfloatC0.887[-5.7/2.6] Type value at Z and model (V-K)=0.887magstat.paramfloatC1.211Type value at Z and model (V-K)=1.211magstat.paramfloatC1.578Type value at Z and model (V-K)=1.578magstat.paramfloatC1.792Type value at Z and model (V-K)=1.792magstat.paramfloatC2.017Type value at Z and model (V-K)=2.017magstat.paramfloatC2.290Type value at Z and model (V-K)=2.290magstat.paramfloatC2.585Type value at Z and model (V-K)=2.585magstat.paramfloatC2.966Type value at Z and model (V-K)=2.966magstat.paramfloatC3.475Type value at Z and model (V-K)=3.475magstat.paramfloatC4.329[-0.9/2.5] Type value at Z and model (V-K)=4.329magstat.paramfloatJ/ApJ/810/76/table6LTE Partial I derivatives with respect to Teff and [M], at each grid value of Teff and [M/H], in index units and in units of {sigma} for SDSS spectral resolution for our nine H Lick-XMP indicesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintType[1/4] Partial derivative description (1)meta.codeintIndexLick-XMP index (Fe4383, Fe4531, Fe5015, Fe5270, Fe5335, Fe5406, Mg b, Mg_1_ and Na D)spect.indexcharZ[-6/-0] Model metallicityphys.abund.Z;meta.modelledfloatT6500[-0.8/2] Type value at Z and model temperature 6500Kstat.paramfloatT6000[-0.7/2.3] Type value at Z and model temperature 6000Kstat.paramfloatT5500[-0.6/2.6] Type value at Z and model temperature 5500Kstat.paramfloatT5250[-0.6/2.7] Type value at Z and model temperature 5250Kstat.paramfloatT5000[-0.5/2.9] Type value at Z and model temperature 5000Kstat.paramfloatT4750[-0.5/3] Type value at Z and model temperature 4750Kstat.paramfloatT4500[-0.5/3.2] Type value at Z and model temperature 4500Kstat.paramfloatT4250[-0.6/3.4] Type value at Z and model temperature 4250Kstat.paramfloatT4000[-0.7/3.6] Type value at Z and model temperature 4000Kstat.paramfloatT3750[-1/3.8] Type value at Z and model temperature 3750Kstat.paramfloat