J/A+A/500/L17ivo://CDS.VizieR/J/A+A/500/L17doi:10.26093/cds/vizier.35009017CDSBailey S.Aldering G.Antilogus P.Aragon C.Baltay C.Bongard S.,Buton C.Childress M.Chotard N.Copin Y.Gangler E.Loken S.,Nugent P.Pain R.Pecontal E.Pereira R.Perlmutter S.Rabinowitz D.,Rigaudier G.Runge K.Scalzo R.Smadja G.Swift H.Tao C.,Thomas R.C.Wu C.2017-12-15T10:55:18Z2009-08-11T18:01:57ZCDS support team

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

cds-question@unistra.frsupernovaespectrophotometryWe present a new method to standardize Type Ia supernova (SN Ia) luminosities to ~<0.13mag using flux ratios from a single flux-calibrated spectrum per SN. Using Nearby Supernova Factory spectrophotometry of 58 SNe Ia, we performed an unbiased search for flux ratios that correlate with SN Ia luminosity. After developing the method and selecting the best ratios from a training sample, we verified the results on a separate validation sample and with data from the literature. We identified multiple flux ratios whose correlations with luminosity are stronger than those of light curve shape and color, previously identified spectral feature ratios, or equivalent width measurements. In particular, the flux ratio R(642/443)=Flux(642nm)/Flux(443nm) has a correlation of 0.95 with SN Ia absolute magnitudes. Using this single ratio as a correction factor produces a Hubble diagram with a residual scatter standard deviation of 0.125+/-0.011mag, compared with 0.161+/-0.015mag when fit with the SALT2 light curve shape and color parameters x1 and c. The ratio R(642/443) is an effective correction factor for both extrinsic dust reddening and intrinsic variations such as those of SN 1991T-like and SN 1999aa-like SNe. When combined with broad-band color measurements, spectral flux ratios can standardize SN Ia magnitudes to ~0.12mag. These are the first spectral metrics that give robust improvements over the standard normalization methods based upon light curve shape and color, and they provide among the lowest scatter Hubble diagrams ever published.2009A&A...500L..17Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/500/L17CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/sn : Asiago Supernova Catalogue (Barbon et al., 1999-)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/500/L17https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/500/L17http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/500/L17https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/500/L17https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/500/L17http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/500/L17GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/A+A/500/L17/table1Flux Ratio correlations and Hubble residual stdevrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFitParmsHubble fit standardization parametersmeta.id;stat.fit.paramcharrho.TCorrelations in Training setstat.correlationfloatrho.VCorrelations in Validation setstat.correlationfloatrho.CCorrelations in Combined setstat.correlationfloatGamma? Flux ratio fit slopespect.indexfloatnullablee_Gamma? Flux ratio fit slope errorstat.errorfloatnullablesig.THubble residuals stdev Training setmagstat.stdevfloate_sig.Tstdev errors Training setmagstat.errorfloatsig.VHubble residuals stdev Validation setmagstat.stdevfloate_sig.Vstdev errors Validation setmagstat.errorfloatsig.CHubble residuals stdev Combined setmagstat.stdevfloate_sig.Cstdev errors Combined setmagstat.errorfloatsigmaNormalized Median Absolute Deviationmagstat.stdevfloatJ/A+A/500/L17/table2*SALT2 fit and R(642/443) flux ratiosrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSN Namemeta.id;meta.maincharprimarySet[TVL] T=Training, V=Validation, L=Literaturemeta.idcharzcmbRedshift in CMB framesrc.redshift;pos.heliocentricfloatx1? SALT2 x1 light curve shape parameterstat.fit.paramfloatnullablee_x1? SALT2 x1 parameter errorstat.errorfloatnullablecolor? SALT2 color parameter [~E(B-V)]magphot.color.excessfloatnullablee_color? SALT2 color parameter errormagstat.error;phot.colorfloatnullabledmuBUncorrected Hubble diagram residualmagstat.fit.residualfloate_dmuBHubble diagram residual errormagstat.errorfloatR642/443Flux ratio R(642/443)phot.flux;arith.ratiofloate_R642/443Flux ratio R(642/443) errorstat.errorfloatRc642/443? Decolored Flux ratio Rc(642/443)phot.flux;arith.ratiofloatnullablee_Rc642/443? Decolored Flux ratio Rc(642/443) errorstat.errorfloatnullableRefNon-SNfactory discovery referencemeta.ref;pos.framecharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/A+A/500/L17/table3All flux ratios R, Rc for SNfactory SNerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSN Namemeta.id;meta.maincharSet[TV] T=Training, V=Validationmeta.idcharzcmbRedshift in CMB frame (1)src.redshift;pos.heliocentricfloatx1SALT2 x1 light curve shape parameterstat.fit.paramfloate_x1SALT2 x1 parameter errorstat.errorfloatcolorSALT2 color parameter ~E(B-V)magphot.color.excessfloate_colorSALT2 color parameter errormagstat.error;phot.colorfloatdmuBUncorrected Hubble diagram residualmagstat.fit.residualfloate_dmuBHubble diagram residual errormagstat.errorfloatR642/443Flux ratio R(642/443)phot.flux;arith.ratiofloate_R642/443Flux ratio R(642/443) errorstat.errorfloatR642/417Flux ratio R(642/417)phot.flux;arith.ratiofloate_R642/417Flux ratio R(642/417) errorstat.errorfloatR772/437Flux ratio R(772/437)phot.flux;arith.ratiofloate_R772/437Flux ratio R(772/437) errorstat.errorfloatR642/512Flux ratio R(642/512)phot.flux;arith.ratiofloate_R642/512Flux ratio R(642/512) errorstat.errorfloatR728/398Flux ratio R(728/398)phot.flux;arith.ratiofloate_R728/398Flux ratio R(728/398) errorstat.errorfloatRc642/519Decolored Flux ratio Rc(642/519)phot.flux;arith.ratiofloate_Rc642/519Decolored Flux ratio Rc(642/519) errorstat.errorfloatRc577/642Decolored Flux ratio Rc(577/642)phot.flux;arith.ratiofloate_Rc577/642Decolored Flux ratio Rc(577/642) errorstat.errorfloatRc642/536Decolored Flux ratio Rc(642/536)phot.flux;arith.ratiofloate_Rc642/536Decolored Flux ratio Rc(642/536) errorstat.errorfloatRc676/642Decolored Flux ratio Rc(676/642)phot.flux;arith.ratiofloate_Rc676/642Decolored Flux ratio Rc(676/642) errorstat.errorfloatRc642/443Decolored Flux ratio Rc(642/443)phot.flux;arith.ratiofloate_Rc642/443Decolored Flux ratio Rc(642/443) errorstat.errorfloat