J/ApJ/831/7ivo://CDS.VizieR/J/ApJ/831/7doi:10.26093/cds/vizier.18310007CDSShen Y.Brandt W.N.Richards G.T.Denney K.D.Greene J.E.Grier C.J.,Ho L.C.Peterson B.M.Petitjean P.Schneider D.P.Tao C.Trump J.R.2021-04-28T12:27:38Z2017-02-22T10:28:37ZCDS support team

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

cds-question@unistra.frquasarsspectroscopyredshiftedsurveysQuasar emission lines are often shifted from the systemic velocity due to various dynamical and radiative processes in the line-emitting region. The level of these velocity shifts depends both on the line species and on quasar properties. We study velocity shifts for the line peaks (not the centroids) of various narrow and broad quasar emission lines relative to systemic using a sample of 849 quasars from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project. The coadded (from 32 epochs) spectra of individual quasars have sufficient signal-to-noise ratio (S/N) to measure stellar absorption lines to provide reliable systemic velocity estimates, as well as weak narrow emission lines. The large dynamic range in quasar luminosity (~2dex) of the sample allowed us to explore potential luminosity dependence of the velocity shifts. We derive average line peak velocity shifts as a function of quasar luminosity for different lines, and quantify their intrinsic scatter. We further quantify how well the peak velocity can be measured as a function of continuum S/N, and demonstrate that there is no systematic bias in the velocity measurements when S/N is degraded to as low as ~3 per SDSS pixel (~69kms/s). Based on the observed line shifts, we provide empirical guidelines on redshift estimation from [OII]{lambda}3727, [OIII]{lambda}5007, [NeV]{lambda}3426, MgII, CIII], HeII{lambda}1640, broad H{beta}, CIV, and SiIV, which are calibrated to provide unbiased systemic redshifts in the mean, but with increasing intrinsic uncertainties of 46, 56, 119, 205, 233, 242, 400, 415, and 477kms/s, in addition to the measurement uncertainties. These results demonstrate the infeasibility of measuring quasar redshifts to better than ~200kms/s with only broad lines.2016ApJ...831....7Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/831/7CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/270 : SDSS quasar catalog: tenth data release (Paris+, 2014)VII/269 : SDSS Quasar Catalog, DR9Q (Paris+, 2012)J/ApJ/818/30 : Lag measurements of 15 z<0.8 QSOs from SDSS-RM (Shen+, 2016)J/ApJ/817/55 : NIR spectroscopy of 1.5<z<3.5 broad-band QSOs (Shen, 2016)J/ApJ/811/91 : SDSS-RM project: z<1 QSO host galaxies (Matsuoka+, 2015)J/ApJ/805/96 : SDSS-RM project: velocity dispersions of QSOs (Shen+, 2015)J/ApJS/217/26 : Lick AGN monitoring 2011: light curves (Barth+, 2015)J/ApJS/216/4 : SDSS-RM project: technical overview (Shen+, 2015)J/MNRAS/431/836 : Type 1 AGN at low z. III. (Stern+, 2013)J/ApJS/201/23 : Spectroscopy of 88 z<0.7 SDSS QSOs (Eracleous+, 2012)J/ApJ/753/125 : NIR spectroscopy follow-up of 60 SDSS-DR7 QSOs (Shen+, 2012)J/MNRAS/423/600 : Type-1 low-z AGN emission properties (Stern+, 2012)J/ApJ/737/71 : The [OIII] emission line in SDSS AGNs (Zhang+, 2011)J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)J/MNRAS/405/2302 : Improved redshifts for SDSS quasar spectra (Hewett+, 2010)J/AJ/130/381 : Blueshifted [O III] emission (Boroson+, 2005)http://www.sdss3.org/ : SDSS-III home pagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/831/7https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/831/7http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/831/7https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/831/7https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/831/7http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/831/7GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/831/7/catalog (Peak velocity measurements for each of the 849 quasars in the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/831/7/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/831/7/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/831/7/catalog?GETtext/xml+votable180.050000true213.654341111153.07299305560.0055555555555555565/2856 6/10741 10743 10749 11402 11403 11406 11428 11430 11432 11433 11436https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/831/7?format=asciidefaultJ/ApJ/831/7/catalogPeak velocity measurements for each of the 849 quasars in the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) sampleSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRMID[0/848]? Unique RMID number (1)meta.idintnullablez[0.1/4.4] Pipeline redshift (Z)src.redshiftfloatlogL1350[44.3/47]? Continuum luminosity at rest 1350{AA}, in erg/s (LOGL1350)log(1e-07W)phys.luminosityfloatnullablee_logL1350[0.0003/0.03]? logL1350 uncertaintylog(1e-07W)stat.errorfloatnullablelogL1700[44.1/47]? Continuum luminosity at rest 1350{AA}, in erg/s (LOGL1700)log(1e-07W)phys.luminosityfloatnullablee_logL1700[0.0002/0.02]? logL1700 uncertaintylog(1e-07W)stat.errorfloatnullablelogL3000[42.2/46.8]? Continuum luminosity at rest 3000{AA}, in erg/s (LOGL3000)log(1e-07W)phys.luminosityfloatnullablee_logL3000[0.0001/0.04]? logL3000 uncertaintylog(1e-07W)stat.errorfloatnullablelogL5100[42.6/45.7]? Continuum luminosity at rest 5100{AA}, in erg/s (LOGL5100)log(1e-07W)phys.luminosityfloatnullablee_logL5100[0.0002/0.03]? logL5100 uncertaintylog(1e-07W)stat.errorfloatnullableVHb[-3025/3088]? Peak velocity (wrt pipeline z) for broad H{beta} (HBETA_BR)km/sspect.dopplerVelocdoublenullablee_VHb[2/2546]? VHb uncertainty (2)km/sstat.errorfloatnullableVOIIIc[-319/341]? Peak velocity (wrt pipeline z) for the core [OIII] (OIII5008C)km/sspect.dopplerVelocfloatnullablee_VOIIIc[0.9/83]? VOIIIc uncertainty (2)km/sstat.errorfloatnullableVOIIIf[-906/760]? Peak velocity (wrt pipeline z) for the full [OIII] (OIII5008A)km/sspect.dopplerVelocfloatnullablee_VOIIIf[0.8/1227]? VOIIIf uncertainty (2)km/sstat.errorfloatnullableVCaII[-1351/802]? Peak velocity (wrt pipeline z) for CaII (CAII3934)km/sspect.dopplerVelocdoublenullablee_VCaII[6/992]? VCaII uncertainty (2)km/sstat.errorfloatnullableVOII[-1094/2085] Peak velocity (wrt pipeline z) for [OII] (OII3728)km/sspect.dopplerVelocdoublee_VOII[1/858]? VOII uncertainty (2)km/sstat.errorfloatnullableVNeV[-2983/3013]? Peak velocity (wrt pipeline z) for [NeV]3426 (NEV3426)km/sspect.dopplerVelocdoublenullablee_VNeV[0.9/1035]? VNeV uncertainty (2)km/sstat.errorfloatnullableVMgII[-2699/3292]? Peak velocity (wrt pipeline z) for MgII (MGII)km/sspect.dopplerVelocdoublenullablee_VMgII[8/2003]? VMgII uncertainty (2)km/sstat.errorfloatnullableVCIII[-4513/4573]? Peak velocity (wrt pipeline z) for CIII] (CIII)km/sspect.dopplerVelocdoublenullablee_VCIII[8/4426]? VCIII uncertainty (2)km/sstat.errorfloatnullableVComp[-8937/4573]? Peak velocity (wrt pipeline z) for the CIII]/SiIII]/AlIII complex (CIIIA)km/sspect.dopplerVelocdoublenullablee_VComp[8/4426]? VComp uncertainty (2)km/sstat.errorfloatnullableVHeII[-2390/1963]? Peak velocity (wrt pipeline z) for HeII1640 (HEII1640)km/sspect.dopplerVelocdoublenullablee_VHeII[0.7/1634]? VHeII uncertainty (2)km/sstat.errorfloatnullableVCIV[-4316/2226]? Peak velocity (wrt pipeline z) for CIV (CIV)km/sspect.dopplerVelocdoublenullablee_VCIV[6/2140]? VCIV uncertainty (2)km/sstat.errorfloatnullableVSi/OIV[-2882/2744]? Peak velocity (wrt pipeline z) for SiIV/OIV] (SIIV)km/sspect.dopplerVelocdoublenullablee_VSi/OIV[11/843]? VSi/OIV uncertainty (2)km/sstat.errorfloatnullableSCatDisplay data from Matsuoka+, 2015, J/ApJ/811/91 and Shen+, 2015, J/ApJ/805/96, for this quasarmeta.ref.urlintnullableSloanDisplay the online SDSS data for the nearest objectmeta.ref.urlchar_RAPositions from Shen+, 2015, J/ApJS/216/4 (right ascension part)degpos.eq.ra;meta.main_DEPositions from Shen+, 2015, J/ApJS/216/4 (declination part)degpos.eq.dec;meta.main