J/ApJ/920/33ivo://CDS.VizieR/J/ApJ/920/33doi:10.26093/cds/vizier.19200033CDSDekany I.,Grebel E.K.,Pojmanski G.2023-03-16T08:29:45Z2023-02-28T07:33:22ZCDS support team

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

cds-question@unistra.frvariable-starsinfrared-photometryvisible-astronomyphotometrymetallicityWe have revisited the problem of metallicity prediction of RR-Lyrae stars from their near-infrared light curves in the Cousins I wave band. Our study is based on high-quality time series photometry and state-of-the-art high-resolution spectroscopic abundance measurements of 80 fundamental-mode (RRab) and 24 first-overtone (RRc) stars, spanning ~[-2.7;+0.18]dex and ~[-3;-0.5]dex ranges, respectively. Employing machine-learning methods, we investigated various light-curve representations and regression models to identify their optimal form for our objective. Accurate new empirical relations between the [Fe/H] iron abundance and the light-curve parameters have been obtained using Bayesian regression for both RRab and RRc stars with mean absolute prediction errors of 0.16dex and 0.18dex, respectively. We found that earlier I-band [Fe/H] estimates had a systematic positive bias of up to ~0.4dex in the metal-poor regime. Our new predictive models were deployed on large ensembles of RR Lyrae stars to obtain photometric metallicity distribution functions (MDFs) for various old stellar populations in and around the Milky Way. We find that the mode of the old bulge component's MDF is approximately -1.4dex, in remarkable agreement with the latest spectroscopic result. Furthermore, we derive MDF modes of -1.83, -2.13, and -1.77dex for the Large and Small Magellanic Clouds and the Sagittarius dwarf galaxy, respectively.2021ApJ...920...33Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/920/33CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/108/1016 : Kinematics of local RR lyrae stars. I. (Layden, 1994)J/AJ/110/2319 : Abundances in RR Lyr variables (Clementini+ 1995)J/A+A/312/111 : [Fe/H] from RR Lyrae light curves (Jurcsik+, 1996)J/A+A/430/1049 : RR Gem BV(RI)c differential photometry (Jurcsik+, 2005)J/A+A/476/307 : Period variations in galactic RRab stars (Le Borgne+, 2007)J/AcA/59/137 : ASAS Galactic fundamental mode RRLyrae star (Szczygiel+, 2009)J/AJ/137/4377 : List of SEGUE plate pairs (Yanny+, 2009)J/ApJS/197/29 : Chemical compositions of 11 RR Lyrae (For+, 2011)J/ApJ/782/59 : Abundances 8 RR Lyrae subclass C variable stars (Govea+, 2014)J/MNRAS/447/2404 : Equivalent width of 21 RR Lyrae stars (Pancino+, 2015)J/ApJ/821/L25 : Bulge RRLyrae Radial Velocity Assay (BRAVA-RR) (Kunder+, 2016)J/AJ/153/96 : Standard Galactic field RR Lyrae I. Photometry (Monson+, 2017)J/ApJ/848/68 : Abundances & RVs of stable & Blazhko RRc stars (Sneden+, 2017)J/ApJ/857/54 : JHKs photometry of VVV RR Lyrae stars (Dekany+, 2018)J/MNRAS/481/1195 : Gaia DR2 RRLyrae stars as standard candles (Muraveva+, 2018)J/A+A/622/A60 : Gaia DR2 misclassified RR Lyrae list (Clementini+, 2019)J/ApJ/883/58 : Cepheids from VVV southern Galactic midplane (Dekany+, 2019)J/ApJ/898/46 : NIR LCs of RRab stars from the VVV survey (Dekany+, 2020)J/ApJ/908/20 : On use field RR Lyrae as galactic probes II. (Crestani+, 2021)J/ApJ/912/144 : Metallicity Gal. RR Lyrae from opt. & IR LCs (Mullen+, 2021)J/ApJ/911/109 : RR Lyrae variable stars in DES Y6 (Stringer+, 2021)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/920/33https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/920/33http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/920/33https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/920/33https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/920/33http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/920/33GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/920/33/table1 (Names and photometric parameters of the RR Lyrae stars in the calibration data set)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/920/33/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/920/33/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/920/33/table1?GETtext/xml+votable180.050000true309.5628181-2.89028220.0055555555555555566/110 4479 4762 6301 7518 8773 9769 10328 10602 11098 11123 11961 12512 12696 12743 15106 15714 16602 16867 16923 17158 17328 18177 18536 19104 19333 20097 20303 21127 21146 21182 24614 24772 24866 24913 25060 25120 25199 25611 25803 25879 25953 26131 26281 26288 26756 26807 26981 27148 27333 27824 28155 28582 28813 30019 30055 30868 30923 31335 31390 31648 31743 32663 33465 33996 34537 35151 35423 35686 36605 38360 38456 38809 39152 39767 40767 40924 40988 40998 41022 41260 41318 42053 42068 42672 44914 44924 45324 45337 45994 46069 46130 46373 46650 47342 47467 47856 48113 48228 48290 48576 48715 48916 491022.367228618189496e-19 2.6706780932288093e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/920/33?format=asciiOpticalInfrareddefaultJ/ApJ/920/33/table1Names and photometric parameters of the RR Lyrae stars in the calibration data setrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCommon namemeta.id;meta.maincharprimaryGaiaGaia DR2 identifiermeta.idASASASAS identifiermeta.idcharTypeRR Lyrae typestat.paramcharBlazhko[0/1] Blazhko modulationmeta.crypticintRefPhotometric reference (1)meta.ref;photcharSimbadSimbad column added by the CDSmeta.ref.urlcharNep[102/3000] Number of observation epochsmeta.numberintPer[0.21/0.81] Pulsation perioddtime.perioddoubleImag[1.07/13.2] Mean I band magnitudemagphot.mag;em.opt.IfloatAt[0.16/0.94] Peak-to-valley amplitude of the light-curve modelsrc.var.amplitudefloatA1[0.07/0.3] First order Fourier term in amplitudesrc.var.amplitudefloate_A1[0.001/0.02] Uncertainty in A1stat.errorfloatA2[0.004/0.17] Second order Fourier term in amplitudesrc.var.amplitudefloate_A2[0.001/0.02] Uncertainty in A2stat.errorfloatA3[0.001/0.12] Third order Fourier term in amplitudesrc.var.amplitudefloate_A3[0.001/0.02] Uncertainty in A3stat.errorfloatphi21[8.71/12.4] Second order Fourier term in phasestat.variance;stat.Fourierfloate_phi21[0.006/0.3] Uncertainty in phi21stat.errorfloatphi31[4.21/7.78] Third order Fourier term in phasestat.variance;stat.Fourierfloate_phi31[0.01/0.9] Uncertainty in phi31stat.errorfloatS/N[77.5/2597] Signal to Noise valuestat.snr;stat.valuedouble_RAPosition from SIMBAD (right ascension part)degpos.eq.ra;meta.mainnullable_DEPosition from SIMBAD (declination part)degpos.eq.dec;meta.mainnullableJ/ApJ/920/33/table3Light-curve parameters in the principal component space of the RR Lyrae stars in the calibration data setNameCommon namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintu1[-3.99/5.75] First linearly uncorrelated u parameterphys.polarization.stokesdoublee_u1[0.03/2] Uncertainty in u1stat.errordoubleu2[-2.04/3.28] Second linearly uncorrelated u parameterphys.polarization.stokesdoublee_u2[0.02/3] Uncertainty in u2stat.errordoubleu3[-8.61/2.12] Third linearly uncorrelated u parameterphys.polarization.stokesdoublee_u3[0.03/4] Uncertainty in u3stat.errordoubleu4[-2.4/2.12] Fourth linearly uncorrelated u parameterphys.polarization.stokesdoublee_u4[0.02/2] Uncertainty in u4stat.errordoubleu5[-1.52/1.61] Fifth linearly uncorrelated u parameterphys.polarization.stokesdoublee_u5[0.02/2] Uncertainty in u5stat.errordoubleu6[-0.83/1.52] Sixth linearly uncorrelated u parameterphys.polarization.stokesdoublee_u6[0.02/0.8] Uncertainty in u6stat.errordoubleJ/ApJ/920/33/table4Spectroscopic metallicities of RR Lyrae stars compiled from the literatureNameCommon namemeta.id;meta.maincharDelta[-0.26/0.16] Computed shift with respect to CFCS dataphys.atmol.lineShift;meta.modelledfloatRefReference code (1)meta.refcharInstInstrument usedinstr.setupcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[Fe/H][-2.99/0.2] Metallicitylog(Sun)phys.abund.Fefloate_[Fe/H][0.04/0.3] Uncertainty in [Fe/H]log(Sun)stat.error;phys.abund.Fefloat