J/A+A/619/A134ivo://CDS.VizieR/J/A+A/619/A134doi:10.26093/cds/vizier.36190134CDSHanke M.Hansen C. J.Koch A.Grebel E.K.2018-12-13T12:53:23Z2018-11-16T08:53:37ZCDS support team

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

cds-question@unistra.fratomic-physicsspectroscopymetallicityeffective-temperatureThe rapidly increasing number of stellar spectra obtained by existing and future large-scale spectroscopic surveys feeds a demand for fast and efficient tools for the spectroscopic determination of fundamental stellar parameters. Such tools should not only comprise customized solutions for one particular survey or instrument, but, in order to enable cross-survey comparability, they should also be capable of dealing with spectra from a variety of spectrographs, resolutions, and wavelength coverages. To meet these ambitious specifications, we developed ATHOS (A Tool for HOmogenizing Stellar parameters), a fundamentally new analysis tool that adopts easy-to-use, computationally inexpensive analytical relations tying flux ratios (FRs) of designated wavelength regions in optical spectra to the stellar parameters effective temperature (Teff), iron abundance ([Fe/H]), and surface gravity (logg). Our Teff estimator is based on FRs from nine pairs of wavelength ranges around the Balmer lines H{beta} and H{alpha}, while for [Fe/H] and logg we provide 31 and 11 FRs, respectively, which are spread between ~4800{AA} and ~6500{AA}; a region covered by most optical surveys. The analytical relations employing these FRs were trained on N=124 real spectra of a stellar benchmark sample that covers a large parameter space of Teff~=4000 to 6500K (spectral types F to K), [Fe/H]~=-4.5 to 0.3dex, and logg~=1 to 5dex, which at the same time reflects ATHOS' range of applicability. We find accuracies of 97K for Teff, 0.16dex for [Fe/H], and 0.26dex for logg, which are merely bounded by finite uncertainties in the training sample parameters. ATHOS' internal precisions can be better by up to 70%. We tested ATHOS on six independent large surveys spanning a wide range of resolutions (R~=2000 to 52000), amongst which are the Gaia-ESO and the SDSS/SEGUE surveys. The exceptionally low execution time (<30ms per spectrum per CPU core) together with a comparison to the literature parameters showed that ATHOS can successfully achieve its main objectives, in other words fast stellar parametrization with cross-survey validity, high accuracy, and high precision. These are key to homogenize the output from future surveys, such as 4MOST or WEAVE.2018A&A...619A.134Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/619/A134CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIII/281 : Gaia FGK benchmark stars v2.1 (Jofre+, 2018)J/ApJ/626/446 : Effective temperature scale of FGK stars (Ramirez+, 2005)J/MNRAS/371/879 : Effective temperatures of 215 FGK giants (Kovtyukh+, 2006)J/A+A/520/A79 : Nearby FGK stars chromospheric activityJ/ApJ/735/41 : Carbon and oxygen abundances in FGK stars (Petigura+, 2011)J/A+A/545/A32 : Chemical abundances of 1111 FGK stars (Adibekyan+, 2012)J/A+A/547/A106 : Li abundances in the FGK dwarfs (Mishenina+, 2012)J/A+A/552/A27 : Stellar activity and kinematics of FGK stars (Murgas+, 2013)J/A+A/556/A86 : FGK dwarf stars limb darkening coefficients (Neilson+, 2013)J/MNRAS/442/220 : Lick indices for FGK stars (Franchini+, 2014)J/MNRAS/445/2223 : Mass estimation for FGK stars (Pinheiro+, 2014)J/ApJ/764/78 : Oxygen abundances in nearby FGK stars (Ramirez+, 2013)J/A+A/575/A89 : Center-to-limb polarization of FGK stars (Kostogryz+, 2015)J/A+A/586/A87 : Center-to-limb polarization of FGK stars (Kostogryz+, 2016)J/MNRAS/456/1221 : FGK dwarfs atmospheric parameters (Ryabchikova+, 2016)J/A+A/606/A94 : Chemical abundances of 1059 FGK stars (Delgado Mena+, 2017)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/619/A134https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/619/A134http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/619/A134https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/619/A134https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/619/A134http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/619/A134GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/619/A134/table2 (Stellar parameters for the benchmark sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/619/A134/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/619/A134/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/619/A134/table2?GETtext/xml+votable180.050000true213.915300319.18240920.0055555555555555566/146 436 798 2923 4376 4574 6159 6219 8767 8779 8845 12424 12704 12793 13020 13028 13114 13301 13829 14385 16115 16666 16935 17136 17245 17343 17420 17425 18483 18778 18907 19924 22120 22205 22300 22518 23011 23096 23705 24715 24775 24827 24942 25385 25554 25595 25891 26025 26302 26347 26457 26538 26552 26975 27162 27857 28336 28664 29703 29765 30233 30577 30878 31427 31683 31748 32343 32889 33273 33281 34012 34595 34684 34709 35532 35750 35775 35875 35913 36035 36084 36135 36221 36693 36697 36745 38072 38216 38986 39157 39647 39893 41721 41763 42081 42248 42331 43310 43360 43445 43641 43786 44208 44281 44364 44542 44575 44653 44771 45050 45797 46506 46704 46796 47344 47389 47698 48394 48731 48736 49078https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/619/A134?format=asciidefaultJ/A+A/619/A134/table1Atomic data for FeI and FeIIIonIon designation (Fe I or Fe II)phys.atmol.ionStagecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambdaWavelength0.1nmem.wldoublechiexExcitation potentialeVphys.atmol.excitationfloatloggfOscillator strengthphys.atmol.oscStrengthfloatJ/A+A/619/A134/table2Stellar parameters for the benchmark sampleSimbadNameSimbad column added by the CDSmeta.idcharIDStar identifiermeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTeffEffective temperatureKphys.temperature.effectiveinte_TeffUncertainty on TeffKstat.error;phys.temperature.effectiveintloggSurface gravityphys.gravityfloate_loggUncertainty on loggstat.errorfloat[Fe/H]Metallicityphys.abund.Zfloate_[Fe/H]Uncertainty on [Fe/H]stat.error;phys.abund.FefloatspectrSpectrographinstrcharSrcFlag[1/4] Source flag (1)meta.code.errorintParFlag[1,2]? Re-determined parameters (2)meta.codechar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.mainnullable_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainnullable