J/ApJ/777/79ivo://CDS.VizieR/J/ApJ/777/79doi:10.26093/cds/vizier.17770079CDSMager V.A.Madore B.F.Freedman W.L.2017-12-06T07:38:16Z2015-05-05T13:27:28ZCDS support team

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

cds-question@unistra.frhst-photometrychemical-abundancesvariable-starsThe impact of metallicity on the Cepheid period-luminosity (P-L) relation is investigated using Hubble Space Telescope Advanced Camera for Surveys V and I images of M101. Variations in the reddening-free Wesenheit parameter (W), which is employed as a proxy for luminosity, are examined as a function of the radial distance from the center of M101 (and thus metallicity). We determine that there is no dependence of the slope on metallicity. However, the intercept is found to depend on metallicity by {gamma}_VI_=-0.33+/-0.12mag.dex^-1^ and {gamma}_VI_=-0.71+/-0.17mag.dex^-1^ using 2{sigma} and 3{sigma} rejection criteria, respectively. Sigma-clipping impacts the derived metallicity dependence, and the 2{sigma} criterion applied likely mitigates blending, particularly in the crowded inner regions of M101. A metallicity-corrected distance for M101 is obtained from 619 Cepheids ({mu}=28.96+/-0.11), a result that agrees with the recently determined SN Ia distance. The metallicity effects described can be bypassed by working at near and mid-infrared wavelengths (e.g., the Carnegie Hubble Program).2013ApJ...777...79Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/777/79CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/hst : HST Archived Exposures Catalog (STScI, 2007)J/AJ/146/114 : Massive stars in M101. I. HST BVI photometry (Grammer+, 2013)J/ApJ/759/146 : Spitzer/IRAC photom. for 37 Galactic Cepheids (Monson+, 2012)J/ApJ/743/176 : BVI photometry of Cepheids in M81 (Gerke+, 2011)J/ApJ/743/76 : Spitzer photometry of LMC Cepheids (Scowcroft+, 2011)J/ApJ/733/124 : Cepheids in M101 observed with HST (Shappee+, 2011)J/ApJS/193/26 : The M33 synoptic stellar survey. I. (Pellerin+, 2011)J/ApJ/715/277 : Insights into the Cepheid distance scale (Bono+, 2010)J/AcA/60/17 : VI light curves of SMC classical Cepheids (Soszynski+, 2010)J/ApJ/699/539 : Cepheids in SN-Ia host galaxies (Riess+, 2009)J/AcA/58/163 : VI light curves of LMC classical Cepheids (Soszynski+, 2008)J/AJ/128/2239 : JHKs photometry of 92 LMC Cepheids (Persson+, 2004)J/AcA/51/221 : OGLE-II. Cepheids in IC 1613 (Udalski+, 2001)J/ApJ/508/491 : M101 Cepheids (Stetson+, 1998)J/ApJ/463/26 : VI photometry of 29 Cepheids in M101. (Kelson+ 1996)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/777/79https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/777/79http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/777/79https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/777/79https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/777/79http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/777/79GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/777/79/table1 (Measured quantities for candidate cepheids)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/777/79/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/777/79/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/777/79/table1?GETtext/xml+votable180.050000true210.9248654.37767610.0055555555555555566/11434https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/777/79?format=asciidefaultJ/ApJ/777/79/table1Measured quantities for candidate cepheidsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFHST field number (F1 or F2; see Figure 1)obs.fieldintIDSource identifier (chN_N_sNNNN)meta.id;meta.maincharRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainVmag[23.4/26.2] The average HST/ACS V band magnitudemagphot.mag;em.opt.Vfloate_Vmag[0.009/0.05] Uncertainty in Vmagmagstat.error;phot.mag;em.opt.VfloatImag[22.6/25.5] The average HST/ACS I band magnitudemagphot.mag;em.opt.Ifloate_Imag[0.006/0.04] Uncertainty in Imagmagstat.error;phot.mag;em.opt.IfloatPer[4.5/29.8] Perioddtime.periodfloatVamp[0.2/1.6] The V band amplitudemagsrc.var.amplitudefloatIamp[0.1/2.8] The I band amplitudemagsrc.var.amplitudefloatr[1/5.4] Angular radial distance from galaxy centerarcminphys.angSizefloat[O/H][-3.6/-3.3] Log O/H metallicityphys.abundfloatSimbadSimbad column added by the CDSmeta.ref.urlchar