J/A+A/620/A99ivo://CDS.VizieR/J/A+A/620/A99doi:10.26093/cds/vizier.36200099CDSGieren W.Storm J.Konorski P.Gorski M.Pilecki B.Thompson I.,Pietrzynski G.Graczyk D.Barnes T.G.Fouque P.Nardetto N.,Gallenne A.Karczmarek P.Suchomska K.Wielgorski P.Taormina M.,Zgirski B.2019-01-07T09:41:47Z2018-12-04T12:20:10ZCDS support team

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

cds-question@unistra.frmagellanic-cloudsvariable-starsphotometryradial-velocityThe extragalactic distance scale builds on the Cepheid period-luminosity (PL) relation. Decades of work have not yet convincingly established the sensitivity of the PL relation to metallicity. This currently prevents a determination of the Hubble constant accurate to 1% from the classical Cepheid-SN Ia method. In this paper we carry out a strictly differential comparison of the absolute PL relations obeyed by classical Cepheids in the Milky Way (MW), LMC, and SMC galaxies. Taking advantage of the substantial metallicity difference among the Cepheid populations in these three galaxies, we want to establish a possible systematic trend of the PL relation absolute zero point as a function of metallicity, and to determine the size of such an effect in the optical and near-infrared photometric bands. We used a IRSB Baade-Wesselink-type method to determine individual distances to the Cepheids in our samples in the MW, LMC, and SMC. For our analysis, we used a greatly enhanced sample of Cepheids in the SMC (31 stars) compared to the small sample (5 stars) available in our previous work. We used the distances to determine absolute Cepheid PL relations in the optical and near-infrared bands in each of the three galaxies. Our distance analysis of 31 SMC Cepheids with periods of 4-69 days yields tight PL relations in all studied bands, with slopes consistent with the corresponding LMC and MW relations. Adopting the very accurately determined LMC slopes for the optical and near-infrared bands, we determine the zero point offsets between the corresponding absolute PL relations in the three galaxies. We find that in all bands the metal-poor SMC Cepheids are intrinsically fainter than their more metal-rich counterparts in the LMC and MW. In the K band the metallicity effect is -0.23+/-0.06mag/dex, while in the V,(V-I) Wesenheit index it is slightly stronger, -0.34+/-0.06mag/dex. We find suggestive evidence that the metallicity sensitivity of the PL relation might be nonlinear, being small in the range between solar and LMC Cepheid metallicity, and becoming steeper towards the lower-metallicity regime.2018A&A...620A..99Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/620/A99CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AcA/65/297 : OGLE4 LMC and SMC Cepheids (Soszynski+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/620/A99https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/620/A99http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/620/A99https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/620/A99https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/620/A99http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/620/A99GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/620/A99/list (List of studied stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/620/A99/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/620/A99/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/620/A99/list?GETtext/xml+votable180.050000true9.890875-73.74844440.0055555555555555566/33294-33295 33304 33306 33316-33317 33319 33328https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/620/A99?format=asciidefaultJ/A+A/620/A99/listList of studied starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDOGLE identifiermeta.id;meta.maincharRAJ2000Simbad right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainlogP? logarithm of the period (from table5 of the paper)log(d)time.perioddoublenullableLCShow the K-band light curvesmeta.ref.urlcharNT2? Number of measurements in table2meta.numberintnullableVCShow the velocity curvesmeta.ref.urlcharNT4? Number of measurements in table4meta.numberintnullableVCCorShow the corrected velocity curvesmeta.ref.urlcharNTB1? Number of measurements in tableb1meta.numberintnullableSimbadSimbad column added by the CDSmeta.ref.urlcharJ/A+A/620/A99/table2K-band light curve datarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDOGLE identifiermeta.id;meta.maincharHJDHeliocentric Julian Datedtime.epochdoubleKmagK-band magnitude in UKIRT systemmagphot.mag;em.IR.Kfloate_KmagError estimate on K-band magnitudemagstat.error;phot.mag;em.IR.KfloatJ/A+A/620/A99/table4Radial velocity datarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDOGLE identifiermeta.id;meta.maincharHJDHeliocentric Julian Datedtime.epochdoubleRVRadial velocitykm/sphys.veloc;pos.heliocentricfloate_RVError estimate on radial velocitykm/sstat.errorfloatInstInstrument usedinstr.setupcharJ/A+A/620/A99/tableb1Radial velocity data corrected for orbital motionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDOGLE identifiermeta.id;meta.maincharPhasePulsation phasetime.phasefloatHJDHeliocentric Julian Datedtime.epochdoubleRVobsObserved Radial velocitykm/sspect.dopplerVelocfloate_RVobsError estimate on rad. velocitykm/sstat.errorfloatRVCorrected radial velocitykm/sphys.veloc;pos.heliocentricfloatRVoffRadial velocity offsetkm/sphys.veloc;arith.difffloat