J/ApJ/508/491ivo://CDS.VizieR/J/ApJ/508/491doi:10.26093/cds/vizier.15080491CDSStetson P.B.Saha A.Ferrarese L.Rawson D.M.Ford H.C.,Freedman W.L.Gibson B.K.Graham J.A.Harding P.Han M.Hill R.J.,Hoessel J.G.Huchra J.P.Hughes S.M.G.Illingworth G.D.Kelson D.D.,Kennicutt R.C.JrMadore B.F.Mould J.R.Phelps R.L.Sakai S.,Silbermann N.A.Turner A.2009-04-17T08:40:45Z2009-04-17T08:35:30ZCDS support team

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

cds-question@unistra.frvariable-starsphotometryWe report on the identification of 255 candidate variable stars in a field located some 1.7' from the center of the late-type spiral galaxy M101 = NGC 5457, based on observations made with the Wide Field and Planetary Camera 2 on board the Hubble Space Telescope. Photometric measurements in the F555W and F814W filters - analyzed independently with the DAOPHOT/ALLFRAME and DoPHOT software suites - have been transformed to the Johnson V and Kron-Cousins I standard magnitude systems. Periods and intensity-averaged mean magnitudes for 61 carefully selected candidate Cepheid variables with periods in the range 10-48 days indicate a reddening-corrected mean distance modulus (m-M)_0_=29.05+/-0.14 (if the true modulus of the Large Magellanic Cloud is 18.50+/-0.10, and if there is no dependence of the period-luminosity relation on metal abundance); results consistent with this are obtained whether or not the sample is expanded to include a larger fraction of the candidates. Applying a metallicity-dependent correction of +0.16+/-0.10mag would increase this estimate to (m-M)_0_= 29.21+/-0.17mag.1998ApJ...508..491Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/508/491CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/463/26 : Extragalactic Distance Scale Key Project. III (Kelson+ 1996)J/ApJ/507/655 : VI photometry of new Cepheids in NGC 2541 (Ferrarese+, 1998)J/ApJ/521/155 : New Cepheids and distance to NGC 4535 (Macri+, 1999)J/ApJ/523/540 : VI photometry of new Cepheids in NGC 3319 (Sakai+, 1999)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/508/491https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/508/491http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/508/491https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/508/491https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/508/491http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/508/491GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/508/491/table2 (Coordinates and mean magnitudes for local standards)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/508/491/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/508/491/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/508/491/table2?GETtext/xml+votable180.050000true210.849354.35420.005555555555555556Cone search capability for table J/ApJ/508/491/table3 (Variable coordinates, periods, and mean magnitudes)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/508/491/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/508/491/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/508/491/table3?GETtext/xml+votable180.050000true210.857754.35180.005555555555555556HST6/11434https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/508/491?format=asciiOpticaldefaultJ/ApJ/508/491/table2Coordinates and mean magnitudes for local standardsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintChip[0/4] WFPC2 chip numbermeta.id;instrint[SSF98]Identification number ([SSF98] NNNNN in Simbad)meta.id;meta.mainintXposX positionpixpos.cartesian.x;instr.detfloatYposY positionpixpos.cartesian.y;instr.detfloatVmagV magnitude (F555W)magphot.mag;em.opt.Vfloate_Vmagrms uncertainty on V magnitudemagstat.error;phot.mag;em.opt.VfloatImagI magnitude (F814W)magphot.mag;em.opt.Ifloate_Imagrms uncertainty on I magnitudemagstat.error;phot.mag;em.opt.Ifloato_VmagNumber of observations in Vmagmeta.numberinto_ImagNumber of observations in Imagmeta.numberint_RAPosition, recomputed by VizieR (about 2arcsec from original position) (right ascension part)degpos.eq.ra;meta.main_DEPosition, recomputed by VizieR (about 2arcsec from original position) (declination part)degpos.eq.dec;meta.mainJ/ApJ/508/491/table3Variable coordinates, periods, and mean magnitudesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[SSF98]Identification number ([SSF98] VNNN in Simbad)meta.id;meta.mainintprimaryDoPhotindicates that a comparison DoPHOT-ALLFRAME exists in table5meta.ref.urlcharChip[1/4] WFPC2 chip numbermeta.id;instrintXposX positionpixpos.cartesian.x;instr.detfloatYposY positionpixpos.cartesian.y;instr.detfloatPerPerioddtime.periodfloate_Perrms uncertainty on Perdstat.errorfloat<Vmag>Mean V magnitude (F555W)magphot.mag;em.opt.Vfloate_<Vmag>rms uncertainty on <Vmag>magstat.error;phot.mag;em.opt.Vfloat<Imag>Mean I magnitude (I814W)magphot.mag;em.opt.Ifloate_<Imag>rms uncertainty on <Imag>magstat.error;phot.mag;em.opt.Ifloat_RAPosition, recomputed by VizieR (about 2arcsec from original position) (right ascension part)degpos.eq.ra;meta.main_DEPosition, recomputed by VizieR (about 2arcsec from original position) (declination part)degpos.eq.dec;meta.mainJ/ApJ/508/491/table5Comparison of ALLFRAME AND DoPHOT for variablesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[SSF98]Identification number ([SSF98] VNNN in Simbad)meta.id;meta.mainintPerDoPHOT perioddtime.periodfloat<Vmag>Mean DoPHOT V magnitude (F555W)magphot.mag;em.opt.Vfloat<Imag>Mean DoPHOT V magnitude (I814W)magphot.mag;em.opt.IfloatDlogPerDoPHOT-ALLFRAME log(Per)log(d)stat.errorfloatD<Vmag>DoPHOT-ALLFRAME <Vmag>magsrc.var.amplitudefloate_D<Vmag>rms uncertainty on D<Vmag>magstat.error;phot.mag;em.opt.VfloatD<Imag>DoPHOT-ALLFRAME <Imag>magsrc.var.amplitudefloate_D<Imag>rms uncertainty on D<Imag>magstat.error;phot.mag;em.opt.Ifloat