J/A+A/506/999ivo://CDS.VizieR/J/A+A/506/999doi:10.26093/cds/vizier.35060999CDSRegnault N.Conley A.Guy J.Sullivan M.Cuillandre J.-C.Astier P.,Balland C.Basa S.Carlberg R.G.Fouchez D.Hardin D.Hook I.M.,Howell D.A.Pain R.Perrett K.Pritchet C.J.2017-07-11T13:08:38Z2009-12-30T15:24:10ZCDS support team

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

cds-question@unistra.frphotometryvisible-astronomysloan-photometryThis is the photometric calibration of the SuperNova Legacy Survey (SNLS) three year dataset. The SNLS corresponds to the DEEP component of the larger Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). The SNLS repeatedly monitors four one square degree fields (labeled D[1-4]) with the MegaCam wide-field imager, in the g, r, i and z bands. u-band observations of the same fields are also available, although not formally part of the SNLS dataset. The non-uniformities of the MegaCam imager photometric response have been mapped as a function of the position on the focal plane. The fluxes, measured on the survey images processed with the CFHT Elixir pipeline, have been corrected for these non-uniformities in order to obtain measurements that are uniform at the ~1% level. The MegaCam passband transmissions were found to be non-uniform, the filters being 3 to 6 nanometers bluer on the edges of the camera than on the center. This result agrees with the filter scans provided by the filter manufacturer (Sagem/REOSC). This has important consequences on the definition of the MegaCam magnitudes: the natural magnitude system depends on the focal plane location where the observations were made. In order not to break the connection between calibrated magnitudes and their physical flux counterparts, we chose to report the *natural magnitudes* of each object, measured in the MegaCam passbands, at the focal plane location where the object was observed. We call this system, "Local Natural Magnitudes". The non-uniformities of the MegaCam effective passbands are small and, for main sequence stellar objects, they may be accounted for using linear color corrections. The relation between the Local Natural Magnitudes of a given star, observed at two locations x_0 and x of the focal plane are: g|x = g|x_0 + dk_g_gr(x) * ( (g-r)|x_0 - (g-r)BD+17|x_0 ) ... z|x = z|x_0 + dk_z_iz(x) * ( (i-z)|x_0 - (i-z)BD+17|x_0 ) where the dk(x) are (position dependant) color terms. We provide dk(x) maps for each MegaCam band (see below). The SNLS 3 year calibration relies on the (Landolt, 1992AJ....104..340) standard star catalog. Landolt fields are observed during each photometric night along with the SNLS fields. Zero-points are derived from these observations. Stable and isolated stars are detected on the SNLS fields and selected as "tertiary standards". The calibrated magnitudes of each tertiary standard obtained under photometric conditions are combined to produce a calibration catalog for each SNLS field. To interpret the tertiary standard magnitudes as physical fluxes, we need a primary standard, i.e. a star with known MegaCam magnitudes and whose spectral energy distribution has been measured absolutely. The SNLS uses BD+17 4708 whose SED has been measured in Bohlin & Gilliland, 2004, Cat. <J/AJ/128/3053> using the HST STIS and NICMOS spectrographs. BD+17 4708 has not been directly observed by SNLS, however, its MegaCam magnitudes were inferred from its known Landolt magnitudes (this paper, table 7). The tertiary star Local Natural Magnitudes are defined so that the associated physical broadband flux f|x is given by: f|x = 10^{-0.4*(m|x-m_ref_)}^*{int}[S_ref(l)_*T(l;x)]dl where m|x is the tertiary star magnitudes at location x on the focal plane, m_ref_ is the MegaCam magnitude of BD+17 4708 (at the center of the focal plane, see table 7 of this paper), S_ref(l)_ is the SED of BD+17 4708 measured in 2004AJ....128.3053B, and T(l;x) is the effective passband of MegaCam at location x. Attached is all the necessary information to tie MegaCam observations to this system. We provide (a) the griz magnitudes of the SNLS tertiary standards for all four SNLS fields (b) the MegaCam open transmission and the ugriz MegaCam filter scans at various position along a diagonal (c) the final uncertainty budget in the form of 3 covariance matrices. The u-band observations of the SNLS DEEP fields are not formally part of the SNLS. Nevetheless we give u-band magnitudes for a subset of the SNLS tertiary stars.2009A&A...506..999Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/506/999CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/506/999https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/506/999http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/506/999https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/506/999https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/506/999http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/506/999GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/506/999/catalog (Tertiary catalog for the SuperNova Legacy Survey (SNLS) fields D1, D2, D3 and D4)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/506/999/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/506/999/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/506/999/catalog?GETtext/xml+votable180.050000true35.99905-4.302740.0055555555555555565/2856 6814 6/11403 11428 17683 17686 17689 17692 17694 27245 27247 48478-48479 48500-485011.7965626859802475e-19 6.090060298487514e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/506/999?format=asciiOpticaldefaultJ/A+A/506/999/catalogTertiary catalog for the SuperNova Legacy Survey (SNLS) fields D1, D2, D3 and D4dkz? Grid z-band dk color term for this objectstat.fit.paramfloatnullableumag? u-band magnitudemagphot.mag;em.opt.UfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFldField nameobs.fieldchargmag? g-band magnitude (Vega-like system)magphot.mag;em.opt.Bfloatnullablee_gmag? Uncertainty on the g-band magnitudemagstat.error;phot.mag;em.opt.Bfloatnullableo_gmag[1,40]? Number of observationsmeta.numberintnullabledkg? Grid g-band dk color term for this objectstat.fit.paramfloatnullablermag? r-band magnitude(Vega-like system)magphot.mag;em.opt.Rfloatnullablee_rmag? Uncertainty on the r-band magnitudemagstat.error;phot.mag;em.opt.Rfloatnullableo_rmag[1,40]? Number of observationsmeta.numberintnullabledkr? Grid r-band dk color term for this objectstat.fit.paramfloatnullableimag? i-band magnitude(Vega-like system)magphot.mag;em.opt.Ifloatnullablee_imag? Uncertainty on the i-band magnitudemagstat.error;phot.mag;em.opt.Ifloatnullableo_imag[1,40]? Number of observationsmeta.numberintnullabledki? Grid i-band dk color term for this objectstat.fit.paramfloatnullablezmag? z-band magnitude(Vega-like system)magphot.mag;em.opt.Ifloatnullablee_zmag? Uncertainty on the z-band magnitudemagstat.error;phot.mag;em.opt.Ifloatnullableo_zmag[1,40]? Number of observationsmeta.numberintnullablee_umag? uncertainty on the u-band magnitudemagstat.error;phot.mag;em.opt.Ufloatnullableo_umag? number of observationsmeta.numberintnullabledku? grid u-band dk color term for this objectstat.fit.paramfloatnullableRAJ2000Right ascension, in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination, in decimal degrees (J2000)degpos.eq.dec;meta.mainJ/A+A/506/999/table13Open transmission of the MegaCam imager (no filters)WLWavelength0.1nmem.wlfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintOT[0,1] Open Transmission (no filters) (1)phys.transmissionfloatJ/A+A/506/999/filtersCombined table from original tablesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFFilter namemeta.code;instr.filtercharWLWavelength0.1nmem.wlintT000[0,1] Transmission at the center of the filterphys.transmission;instr.filterfloatT023[0,1] Transmission at 23mm from the centerphys.transmission;instr.filterfloatT047[0,1] Transmission at 47mm from the centerphys.transmission;instr.filterfloatT070[0,1] Transmission at 70mm from the centerphys.transmission;instr.filterfloatT093[0,1] Transmission at 93mm from the centerphys.transmission;instr.filterfloatT117[0,1] Transmission at 117mm from the centerphys.transmission;instr.filterfloatT140[0,1] Transmission at 140mm from the centerphys.transmission;instr.filterfloatT163[0,1] Transmission at 163mm from the centerphys.transmission;instr.filterfloatT186[0,1] Transmission at 186mm from the centerphys.transmission;instr.filterfloatT210[0,1] Transmission at 210mm from the centerphys.transmission;instr.filterfloatJ/A+A/506/999/tabled1Full covariance matrix of the BD+17 4708 MegaCam and Landolt magnitude uncertaintiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintC1Covariance matrix coefficient ({Delta}g)stat.covariancedoubleC2Covariance matrix coefficient ({Delta}r)stat.covariancedoubleC3Covariance matrix coefficient ({Delta}i)stat.covariancedoubleC4Covariance matrix coefficient ({Delta}z)stat.covariancedoubleC5Covariance matrix coefficient (U_ref_)stat.covariancedoubleC6Covariance matrix coefficient (B_ref_)stat.covariancedoubleC7Covariance matrix coefficient (V_ref_)stat.covariancedoubleC8Covariance matrix coefficient (R_ref_)stat.covariancedoubleC9Covariance matrix coefficient (I_ref_)stat.covariancedoubleJ/A+A/506/999/tabled2Covariance matrix of the uncertainties affecting (1) the differences between the tertiary MegaCam magnitudes and the MegaCam magnitudes of BD+17 4708 and (2) the Landolt magnitudes of BD+17 4708recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintC1Covariance matrix coefficient ({Delta}g)stat.covariancedoubleC2Covariance matrix coefficient ({Delta}r)stat.covariancedoubleC3Covariance matrix coefficient ({Delta}i)stat.covariancedoubleC4Covariance matrix coefficient ({Delta}z)stat.covariancedoubleC5Covariance matrix coefficient (U_ref_)stat.covariancedoubleC6Covariance matrix coefficient (B_ref_)stat.covariancedoubleC7Covariance matrix coefficient (V_ref_)stat.covariancedoubleC8Covariance matrix coefficient (R_ref_)stat.covariancedoubleC9Covariance matrix coefficient (I_ref_)stat.covariancedoubleJ/A+A/506/999/tabled3Covariance matrix of the uncertainties affecting the synthetic instrumental magnitudes of BD+17 4708recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintC1Covariance matrix coefficient ({Delta}g)stat.covariancedoubleC2Covariance matrix coefficient ({Delta}r)stat.covariancedoubleC3Covariance matrix coefficient ({Delta}i)stat.covariancedoubleC4Covariance matrix coefficient ({Delta}z)stat.covariancedoubleC5Covariance matrix coefficient (U_ref_)stat.covariancedoubleC6Covariance matrix coefficient (B_ref_)stat.covariancedoubleC7Covariance matrix coefficient (V_ref_)stat.covariancedoubleC8Covariance matrix coefficient (R_ref_)stat.covariancedoubleC9Covariance matrix coefficient (I_ref_)stat.covariancedouble