J/A+A/534/A95ivo://CDS.VizieR/J/A+A/534/A95doi:10.26093/cds/vizier.35340095CDSStorm J.Gieren W.Fouque P.Barnes T.G.Soszynski I.Pietrzynski G.,Nardetto N.Queloz D.2017-06-26T11:49:14Z2011-10-11T09:07:04ZCDS support team

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

cds-question@unistra.frmagellanic-cloudsvariable-starsstellar-distanceradial-velocityThe extragalactic distance scale builds directly on the Cepheid Period-Luminosity (PL) relation as delineated by the sample of Cepheids in the Large Magellanic Cloud (LMC). However, the LMC is a dwarf irregular galaxy, quite different from the massive spiral galaxies used for calibrating the extragalactic distance scale. Recent investigations suggest that not only the zero-point but also the slope of the Milky Way PL relation differ significantly from that of the LMC, casting doubts on the universality of the Cepheid PL relation. We want to make a differential comparison of the PL relations in the two galaxies by delineating the PL relations using the same method, the infrared surface brightness method (IRSB), and the same precepts. The IRSB method is a Baade-Wesselink type method to determine individual distances to Cepheids. We apply a newly revised calibration of the method as described in an accompanying paper (Paper I, Cat. J/A+A/534/A94) to 36 LMC and five SMC Cepheids and delineate new PL relations in the V,I,J, & K bands as well as in the Wesenheit indices in the optical and near-IR. We present 509 new and accurate radial velocity measurements for a sample of 22 LMC Cepheids, enlarging our earlier sample of 14 stars to include 36 LMC Cepheids. The new calibration of the IRSB method is directly tied to the recent HST parallax measurements to ten Milky Way Cepheids, and we find a LMC barycenter distance modulus of 18.45+/-0.04 (random error only) from the 36 individual LMC Cepheid distances. In the J,K bands we find identical slopes for the LMC and Milky Way PL relations and only a weak metallicity effect on the zero points (consistent with a zero effect), metal poor stars being fainter. In the optical we find the Milky Way slopes are slightly shallower than the LMC slopes (but again consistent with no difference in the slopes) and small effects on the zero points. However, the important Wesenheit index in V,(V-I) shows a metallicity effect on the slope and on the zero point which is likely to be significant. We find a significant metallicity effect on the Wvi index gamma(Wvi)=-0.23+/-0.10mag/dex as well as an effect on the slope. The K-band PL relation on the other hand is found to be an excellent extragalactic standard candle being metallicity insensitive in both slope and zero-point and at the same time being reddening insensitive and showing the least internal dispersion.2011A&A...534A..95Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/534/A95CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/534/A94 : Milky Cepheids radial velocities (Storm+, 2011)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/534/A95https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/534/A95http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/534/A95https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/534/A95https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/534/A95http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/534/A95GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/534/A95/table3 (Distances and absolute magnitudes for the LMC Cepheids calculated using the precepts given in Paper I (2011A&A...534A..95S), using the new p-factor relation)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/534/A95/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/534/A95/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/534/A95/table3?GETtext/xml+votable180.050000true78.3291667-65.49166670.0055555555555555566/33051-33054 33073 33076-33078 33084 33094 33098 33100 33103-33104 33106 33110 33113 33120 33122-33123 33136-33137https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/534/A95?format=asciiOpticaldefaultJ/A+A/534/A95/table3Distances and absolute magnitudes for the LMC Cepheids calculated using the precepts given in Paper I (2011A&A...534A..95S), using the new p-factor relationNameStar namemeta.id;meta.maincharprimaryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVSimbad column added by the CDSmeta.ref.urlcharlogPPeriodlog(d)time.perioddoubledNear-IR surface brightness (IRSB) distancekpcpos.distancefloate_drms uncertainty on dkpcstat.errorfloat(m-M)0Distance modulusmagphot.mag.distModfloate_(m-M)0rms uncertainty on (m-M)0magstat.errorfloatVMAGAbsolute V magnitudemagphys.magAbs;em.opt.VfloatIMAG? Absolute I magnitudemagphys.magAbs;em.opt.IfloatnullableJMAGAbsolute J magnitudemagphys.magAbs;em.IR.JfloatHMAG? Absolute H magnitudemagphys.magAbs;em.IR.HfloatnullableKMAGAbsolute K magnitudemagphys.magAbs;em.IR.KfloatWVI? Wesenheits reddening-free W_VI__ index (W_VI_=I-2.55(V-I))magphot.color.reddFreefloatnullableWJKWesenheits reddening-free W_JK_ index (W_JK_=Ks-0.686(J-Ks ))magphot.color.reddFreefloatE(B-V)Adopted reddeningmagphot.color.excessfloatDphiAdopted phase shift between spectroscopic and photometric angular diametersstat.fit.paramfloatd(m-M)Magnitude correction to refer the distance moduli to the LMC barycentermagphot.mag;arith.difffloatSimbadNameSimbad column added by the CDSmeta.idchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/A+A/534/A95/table2Time stamps and radial velocitiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameVariable star identifiermeta.id;meta.maincharHJDHeliocentric Julian Datedtime.epochdoubleHRVHeliocentric Radial Velocitykm/sspect.dopplerVeloc;pos.heliocentricfloat