J/ApJ/633/638ivo://CDS.VizieR/J/ApJ/633/638doi:10.26093/cds/vizier.16330638CDSWilhite B.C.Vanden Berk D.E.Kron R.G.Schneider D.P.Pereyra N.,Brunner R.J.Richards G.T.Brinkmann J.V.2018-01-05T08:55:46Z2014-11-12T13:38:06ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiquasarsvisible-astronomysloan-photometryredshiftedSDSS repeat spectroscopic observations have resulted in multiepoch spectroscopy for 2500 quasars observed more than 50 days apart. From this sample, calibrating against stars observed simultaneously, we identify 315 quasars that have varied significantly between observations (with respect to assumed nonvariable stars observed concurrently). These variable quasars range in redshift from 0.5 to 4.72. This is the first large quasar sample studied spectroscopically for variability and represents a potentially useful sample for future high-redshift reverberation mapping studies. This also marks the first time the precise wavelength dependence of quasar variability has been determined, allowing both the continuum and emission-line variability to be studied.2005ApJ...633..638Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/633/638CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/270 : SDSS quasar catalog: tenth data release (Paris+, 2014)II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)II/259 : The SDSS Photometric Catalog, Release 3 (Abazajian+ 2005)J/ApJ/728/26 : QSO selection based on phot. variability (Macleod+, 2011)J/A+A/525/A37 : Variability of QSOs in SDSS Stripe 82 (Meusinger+, 2011)J/AJ/142/78 : New 2.2<z<3 quasars from SDSS and UKIDSS (Wu+, 2011)J/ApJ/641/78 : CIV variability in 105 SDSS quasars (Wilhite+, 2006)J/AJ/126/2579 : SDSS QSO catalog. II. First data release (Schneider+, 2003)J/AJ/123/567 : SDSS quasar catalog. I. Early Data Release (Schneider+, 2002)J/AJ/121/2308 : Sloan Digital Sky Survey quasar photometry (Richards+, 2001)J/AJ/121/1872 : FIRST radio-selected QSOs (Helfand+, 2001)J/A+A/321/123 : Optical variability of QSOs (Cristiani+ 1997)J/MNRAS/268/305 : Variability of optically selected quasars (Hook+ 1994)http://www.sdss.org/ : SDSS home pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/633/638https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/633/638http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/633/638https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/633/638https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/633/638http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/633/638GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/633/638/table2 (Variable quasar sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/633/638/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/633/638/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/633/638/table2?GETtext/xml+votable180.050000true150.05570831.20088890.0055555555555555565/1561 4709 6557 6821 6/2 5757 5759 5915 5918 5928 5930 5931 5937 5939 5940 5942 6016 6017 6241 6243 6252 6267 6268 6270 6271 6440 6507 6509 6511 6593 6595 6597 6598 8192 9841 9843 9844 9950 9973 9974 10232 11343 11422 11423 11444 11445 11447 11464 11488 11591 17745 17750 17763 17766 17768 17769 17772 17774 17860 18750 18776 18777 18833 18835 18844 18845 18882 19417 19420 19747 19750 19753 19762 19763 21982 21983 22001 22004 22005 23103 23183 23187 23191 23203 23204 23205 23207 23209 23210 23211 23212 25839 25854 25855 25937 25940 25941 25943 25961 25963 25966 25997 25998 25999 26002 26003 26010 26011 26012 26021 26022 26023 26024 26025 26026 26028 26030 26033 26034 26175 26180 26181 26189 26193 26195 26198 26199 26200 26204 26205 26206 26210 26211 26212 26217 26220 26225 26227 26236 26237 26261 26369 26370 26943 26961 26962 26964 26966 26968 26969 26970 26972 26973 26974 26993 27029 27237 27245 27250 27281 27282 27283 27289 27292 27648 31400 31402 450532.85864675833786e-19 3.5010283109654867e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/633/638?format=asciiOpticaldefaultJ/ApJ/633/638/table2Variable quasar samplez[0.5/4.8] Redshift (2)src.redshiftfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSDSSJSDSS name (HHMMSS.ss+DDMMSS.s) (1)meta.id;meta.maincharMJD(H)Modified Julian Date of High-S/N datadtime.epochintMJD(L)Modified Julian Date of Low-S/N datadtime.epochintDelT[17.5/270.4] Rest-frame time lag {Delta}{tau}dtime.intervalfloatrmag[16.8/21.6] Apparent SDSS r band magnitude (2)magphot.mag;em.opt.RfloatrMAGAbsolute SDSS r band magnitude (2)magphys.magAbsfloatS/N(H)[1.7/54] SDSS r band High-S/N ratiostat.snrfloatS/N(L)[0.7/42] SDSS r band Low-S/N ratiostat.snrfloatSloanDisplay the online SDSS data for the nearest objectmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharNEDSimbad column added by the CDSmeta.refchar_RAPositions from SDSS names (right ascension part)degpos.eq.ra;meta.main_DEPositions from SDSS names (declination part)degpos.eq.dec;meta.main