J/ApJ/843/30ivo://CDS.VizieR/J/ApJ/843/30doi:10.26093/cds/vizier.18430030CDSZhu D.Sun M.Wang T.2018-05-16T07:00:24Z2018-03-08T15:44:42ZCDS support team

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

cds-question@unistra.frquasarsvisible-astronomyspectroscopyline-intensitiesredshiftedWe investigate the relationship between the MgII{lambda}2798 emission line and the 3000{AA} continuum variations using a sample of 68 intermediate-redshift (z~0.65-1.50) broad-line quasars spanning a bolometric luminosity range of 44.49erg/s<=logL_bol_<=46.31erg/s (Eddington ratio from ~0.026 to 0.862). This sample is constructed from SDSS-DR7Q and BOSS-DR12Q, each with at least two spectroscopic epochs in SDSS-I/II/III surveys. In addition, we adopt the following signal-to-noise ratio (S/N) selection criteria: (a) for MgII and the 3000{AA} continuum, S/N>=10; and (b) for narrow lines, S/N>=5. All our quasar spectra are recalibrated based on the assumption of constant narrow emission- line fluxes. In an analysis of spectrum-to-spectrum variations, we find a fairly close correlation (Spearman {rho}=0.593) between the variations in broad MgII and in the continuum. This is consistent with the idea that MgII is varying in response to the continuum emission variations. Adopting the modified weighted least squares regression method, we statistically constrain the slopes (i.e., the responsivity {alpha} of the broad MgII) between the variations in both components for the sources in different luminosity bins after eliminating intrinsic biases introduced by the rescaling process itself. It is shown that the responsivity is quite small (average {bar}{alpha}~0.464) and anti- correlates with the quasar luminosity. Our results indicate that high signal- to-noise flux measurements are required to robustly detect the intrinsic variability and the time lag of the MgII line.2017ApJ...843...30Zhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/843/30CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/282 : The SDSS Photometric Catalog, Release 6 (Adelman-McCarthy+, 2007)VI/64 : Recombination line intensities for hydrogenic ions (Storey+, 1995)VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)VII/279 : SDSS quasar catalog: twelfth data release (Paris+, 2017)J/ApJ/613/682 : AGN central masses & broad-line region sizes (Peterson+, 2004)J/ApJ/633/638 : Variable quasar sample from SDSS (Wilhite+, 2005)J/ApJS/166/470 : SDSS-Spitzer type I QSOs IR photometry (Richards+, 2006)J/ApJ/705/L76 : AGNs with double-peaked [OIII] lines (Wang+, 2009)J/ApJ/708/427 : Type 2 AGNs with double-peaked [OIII] lines (Liu+, 2010)J/ApJ/732/121 : V-band and H{beta} monitoring of Z299-15 (Barth+, 2011)J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)J/ApJ/755/60 : Reverberation mapping for 5 Seyfert 1 galaxies (Grier+, 2012)J/ApJ/753/125 : NIR spectroscopy follow-up of 60 SDSS-DR7 QSOs (Shen+, 2012)J/ApJ/818/30 : Lag measurements for z<0.8 QSOs from the SDSS-RM (Shen+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/843/30https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/843/30http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/843/30https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/843/30https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/843/30http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/843/30GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/843/30/qsos (List of unique quasars; table added by CDS)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/843/30/qsos?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/843/30/qsos?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/843/30/qsos?GETtext/xml+votable180.050000true5.76313611.25933390.0055555555555555565/4438 6/674 4142 4154 4554 5151 5562 5885 5937 6013 6515 6558 6608 6618 7252 7276 7287 7404 8934 9613 9615 9636 9637 10409 10743 10878 10966 11011 11017 11104 11403 11425 11427 11432 11812 13334 17471 17515 17764 17767 17777 18023 18097 19691 19694 19769 20024 23198 26011 26075 26181 26871 26962 27371 27607 27732 28054 28129 28155 28245 28258 28344 28389https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/843/30?format=asciiOpticaldefaultJ/ApJ/843/30/table1* dataCatQuasar catalog observation is included inobs.param;obscharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDIdentification number of our data pairs in this papermeta.idintSDSSSDSS object name (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharPlateSDSS Plate numbermeta.id;instr.plateintFiberSDSS Fiber numbermeta.idintMJDModified Julian Date of observationdtime.epochintEW[18.4/195.5] Broad Mg II equivalent width (1)spect.line.eqWidthfloatlogMg2[36.8/42.5] log narrow MgII line luminosity (2)log(1e-07W)phys.luminosityfloatlogNe4[0/42.3] log Ne IV (3426{AA}) line luminosity (2)log(1e-07W)phys.luminosityfloatlogO2[40.4/45.1] log O II (3726, 3729{AA}) line luminosity (2)log(1e-07W)phys.luminosityfloatlogNe3[40.4/42.4] log NeIII (3869{AA}) line luminosity (2)log(1e-07W)phys.luminosityfloatlogO3[0/43.4] log OIII (5008{AA}) line luminosity (2)log(1e-07W)phys.luminosityfloatz[0.6/1.5] Improved quasar redshift from DR7Q and DR12Qsrc.redshiftfloatlog3000[43.7/45.7] log 3000{AA} continuum luminosity (2)log(1e-07W)phys.luminosityfloatNr[1/5] Number or narrow-lines used in final flux recalibrationmeta.idintSpInteractive spectrum from SDSSmeta.ref.urlcharJ/ApJ/843/30/qsosList of unique quasars; table added by CDSSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNsmeta.numberintnullableSDSSSDSS object name (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharprimaryz[0.6/1.5] Improved quasar redshift from SDSS DR7Q and DR12Q (as in table 1)src.redshiftfloatDR12QDisplay data from the SDSS quasar catalog -DR12 (VII/279) within 1"meta.ref.urlintnullableDR7+DR12Display data from the SDSS photometric catalog -DR7 (II/294) and -DR12 (V/147) within 0.5"meta.ref.urlcharSloanDisplay the online SDSS data for the nearest objectmeta.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