J/ApJ/836/232ivo://CDS.VizieR/J/ApJ/836/232doi:10.26093/cds/vizier.18360232CDSBrown P.J.Landez N.J.Milne P.A.Stritzinger M.D.2017-12-13T19:44:59Z2017-11-08T14:15:49ZCDS support team

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

cds-question@unistra.frsupernovaeultraviolet-photometryvisible-astronomybroad-band-photometryThe intrinsic colors of Type Ia supernovae (SNe Ia) are important to understanding their use as cosmological standard candles. Understanding the effects of reddening and redshift on the observed colors are complicated and dependent on the intrinsic spectrum, the filter curves, and the wavelength dependence of reddening. We present ultraviolet and optical data of a growing sample of SNe Ia observed with the Ultraviolet/Optical Telescope on the Swift spacecraft and use this sample to re-examine the near-UV (NUV) colors of SNe Ia. We find that a small amount of reddening (E(B-V)=0.2mag) could account for the difference between groups designated as NUV-blue and NUV-red, and a moderate amount of reddening (E(B-V)=0.5mag) could account for the whole NUV-optical differences. The reddening scenario, however, is inconsistent with the mid-UV colors and color evolution. The effect of redshift alone only accounts for part of the variation. Using a spectral template of SN2011fe, we can forward model the effects of redshift and reddening and directly compare those with the observed colors. We find that some SNe are consistent with reddened versions of SN2011fe, but most SNe Ia are much redder in the uvw1-v color than SN2011fe reddened to the same b-v color. The absolute magnitudes show that two out of five NUV-blue SNe Ia are blue because their near-UV luminosity is high, and the other three are optically fainter. We also show that SN 2011fe is not a "normal" SN Ia in the UV, but has colors placing it at the blue extreme of our sample.2017ApJ...836..232Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/836/232CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/131/527 : UBVRI light curves of 44 type Ia supernovae (Jha+, 2006)J/ApJ/659/122 : Improved distances to type Ia supernovae (Jha+, 2007)J/ApJ/689/377 : PAIRITEL SNe Ia as NIR standard candles (Wood-Vasey+, 2008)J/AJ/137/4517 : UVOT light curves of supernovae (Brown+, 2009)J/ApJS/185/32 : First-year SDSS-II SN results (Kessler+, 2009)J/ApJ/721/1608 : Absolute UV magnitudes of type Ia SNe (Brown+, 2010)J/AJ/139/120 : Low-redshift Type-Ia supernovae (Folatelli+, 2010)J/ApJ/731/120 : Intrinsic SN Ia light curves (Mandel+, 2011)J/ApJ/753/22 : Swift/UVOT observations of SN 2011fe (Brown+, 2012)J/A+A/554/A27 : 2011fe spectrophotometric time series (Pereira+, 2013)J/A+A/568/A22 : Joint analysis of the SDSS-II and SNLS SNe Ia (Betoule+, 2014)J/ApJS/212/18 : An atlas of UV-to-MIR galaxy SEDs (Brown+, 2014)J/ApJ/796/L18 : Type Ia supernova 2011de UVOT photometry (Brown, 2014)J/MNRAS/438/1391 : Host galaxies of Type Ia SN from PTF (Pan+, 2014)J/AJ/152/102 : Flux conversion factors for Swift/UVOT filters (Brown+, 2016)J/ApJ/826/56 : HST/WFC3 obs. of Cepheids in SN Ia host gal. (Riess+, 2016)http://people.physics.tamu.edu/pbrown/SwiftSN/swift_sn.html : Swift SNe webpagehttp://sne.space/ : The online Open Supernova Cataloghttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/836/232https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/836/232http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/836/232https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/836/232https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/836/232http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/836/232GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/836/232/table1 (Supernovae Ia information)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/836/232/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/836/232/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/836/232/table1?GETtext/xml+votable180.050000true114.0656667-69.50638890.0055555555555555566/4114 4966 5815 5975 7564 8037 8085 9533 11434 17239 18325 18753 18854 19283 21207 23077 23349 24926 25960 28294 28619 31158 32602 33228 37429 38664 38956 44660 449153.322582951404819e-19 5.024903049886575e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/836/232?format=asciiUVOpticaldefaultJ/ApJ/836/232/table1Supernovae Ia informationrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSupernova identifiermeta.id;meta.maincharDm15B[1/1.4] The B band decline rate parameter (1)magsrc.var.amplitudefloate_Dm15B[0.01/0.2] Uncertainty in Dm15Bmagstat.errorfloatw1mag[11/18.8] Swift/UVOT w1 band magnitude at B band peakmagphot.mag;em.UVfloate_w1mag[0.001/0.2] Uncertainty in w1magmagstat.error;phot.magfloatVmag[10/17] The Johnson V band magnitude at B band peakmagphot.mag;em.opt.Vfloate_Vmag[0.001/0.03] Uncertainty in Vmagmagstat.error;phot.mag;em.opt.VfloatB-VThe (B-V) color index at B band peakmagphot.color;em.opt.B;em.opt.Vfloate_B-VUncertainty in (B-V)magstat.error;phot.color;em.opt.BfloatDM[29.1/35.6] Distance modulusmagphot.mag.distModfloate_DM[0.04/0.4] Uncertainty in DMmagstat.errorfloatn_DMMethod used to derive DB (2)meta.notecharr_DMReference for DMmeta.ref;pos.framecharSimbadSimbad column added by the CDSmeta.ref.urlcharNEDNED column added by the CDSmeta.ref.urlchar_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.main