J/ApJ/759/146ivo://CDS.VizieR/J/ApJ/759/146doi:10.26093/cds/vizier.17590146CDSMonson A.J.Freedman W.L.Madore B.F.Persson S.E.Scowcroft V.,Seibert M.Rigby J.R.2017-09-22T16:15:47Z2014-08-22T13:14:54ZCDS support team

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

cds-question@unistra.frinfrared-photometryvariable-starsstellar-distanceinterstellar-reddeningThe Carnegie Hubble Program (CHP) is designed to calibrate the extragalactic distance scale using data from the post-cryogenic era of the Spitzer Space Telescope. The ultimate goal of the CHP is a systematic improvement in the distance scale leading to a determination of the Hubble constant to within an accuracy of 2%. This paper focuses on the measurement and calibration of the Galactic Cepheid period-luminosity (PL, Leavitt) relation using the warm Spitzer/IRAC 1 and 2 bands at 3.6 and 4.5{mu}m. We present photometric measurements covering the period range 4-70 days for 37 Galactic Cepheids. Data at 24 phase points were collected for each star. Three PL relations of the form M=a(log(P)-1)+b are derived. The method adopted here takes the slope a to be -3.31, as determined from the Spitzer Large Magellanic Cloud (LMC) data of Scowcroft et al. (Cat. J/ApJ/743/76). Using the geometric Hubble Space Telescope guide-star distances to 10 Galactic Cepheids, we find a calibrated 3.6{mu}m PL zero point of -5.80+/-0.03. Together with our value for the LMC zero point, we determine a reddening-corrected distance modulus of 18.48+/-0.04mag to the LMC. The mid-IR period-color diagram and the [3.6]-[4.5] color variation with phase are interpreted in terms of CO absorption at 4.5{mu}m. This situation compromises the use of the 4.5{mu}m data for distance determinations.2012ApJ...759..146Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/759/146CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/gcvs : General Catalogue of Variable Stars (Samus+ 2007-2013)J/A+A/550/A70 : Galactic & Magellanic Cloud Cepheids dist. (Groenewegen 2013)J/ApJ/748/107 : A global model for MC and Galactic Cepheids (Pejcha+, 2012)J/ApJ/747/50 : Dist. to Cepheids using the Wesenheit function (Ngeow, 2012)J/MNRAS/419/1637 : Nearby red clump stars JHK observations (Laney+, 2012)J/ApJS/193/12 : JHK photometry of Northern Galactic Cepheids (Monson+, 2011)J/ApJ/743/76 : Spitzer photometry of LMC Cepheids (Scowcroft+, 2011)J/A+A/534/A94 : Milky Way Cepheids radial velocities (Storm+, 2011)J/AJ/139/519 : Carnegie supernova project. SNe Ia (Contreras+, 2010)J/MNRAS/389/1336 : Reddenings of FGK supergiants + Cepheids (Kovtyukh+, 2008)J/A+A/476/73 : Cepheid Period/Luminosity relation calibration (Fouque+, 2007)J/A+A/404/423 : BVI photometry of Galactic Cepheids (Tammann+, 2003)J/A+AS/143/211 : Galactic Cepheids BVRI photometry (Berdnikov+, 2000)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/759/146https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/759/146http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/759/146https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/759/146https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/759/146http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/759/146GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/759/146/table1 (Selected Galactic Cepheids and adopted parallaxes)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/759/146/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/759/146/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/759/146/table1?GETtext/xml+votable180.050000true297.09916727.2863890.0055555555555555566/3045 12934 12968 12971 13201 13288 14295 14409 14625 15633 22219 23622 23922 24411 28779 28831 29081 29095 29104 29523 29665 29897 30128 30258 30321 30322 32074 33804 37303 37931 41461 41862 42153 425003.9193497546148093e-20 6.185923063528282e-20https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/759/146?format=asciiInfrareddefaultJ/ApJ/759/146/table3Spitzer IRAC photometry for Galactic CepheidsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCepheid identifiermeta.id;meta.maincharMJD[55129/55551] Heliocentric MJD (1)dtime.epoch;pos.heliocentricdouble[3.6][0.7/8] Spitzer/IRAC 3.6 micron band magnitudemagphot.mag;em.IR.3-4umfloate_[3.6][0.002/0.03] Uncertainty in [3.6]magstat.errorfloat[4.5][0.9/8] Spitzer/IRAC 4.5 micron band magnitudemagphot.mag;em.IR.4-8umfloate_[4.5][0.001/0.03] Uncertainty in [4.5]magstat.errorfloatJ/ApJ/759/146/table1Selected Galactic Cepheids and adopted parallaxesSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCepheid identifiermeta.id;meta.maincharprimaryNNumber of Spitzer/irac observationsmeta.numberintnullablePerPeriod (derived from logP)dtime.periodfloatlogP[0.5/1.9] log of Period (1)log(d)time.periodfloatRAJ2000Hour of right ascension (J2000) (1)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000) (1)pos.eq.dec;meta.mainE(B-V)[0.01/1.3] Weighted B-V reddening (2)magphot.color.excessfloate_E(B-V)[0.007/0.2] E(B-V) uncertainty (2)magstat.errorfloatPlx1[1.9/3.7]? HST parallax (3)maspos.parallax.photfloatnullablee_Plx1[0.1/0.3]? HST parallax uncertainty (3)masstat.errorfloatnullablePlx2[0.2/3.7]? MS parallax (4)maspos.parallax.photfloatnullablee_Plx2[0.01/0.2]? MS parallax uncertainty (4)masstat.errorfloatnullabler_Plx2[f-j] Reference for Plx2 (5)meta.ref;pos.framecharPlx3[0.2/4.7]? IRSB parallax (6)maspos.parallax.photfloatnullablee_Plx3[0.01/0.4]? IRSB parallax uncertainty (6)masstat.errorfloatnullabler_Plx3[k] Reference for Plx3 (5)meta.ref;pos.framecharIRSBDisplay the data for this star from Storm et al. 2011, Cat. J/A+A/534/A94, if anymeta.numberintnullableLCLight curvesmeta.ref.urlcharGCVSDisplay the Samus et al. 2007-2013, GCVS catalog (B/gcvs) within 3"meta.ref.urlchar