J/ApJ/905/52ivo://CDS.VizieR/J/ApJ/905/52CDSGuo H.Peng J.Zhang K.Burke C.J.Liu X.Sun M.Wang S.Kong M.,Sheng Z.Wang T.He Z.Gu M.2022-09-05T14:04:10Z2022-06-21T08:22:52ZCDS support team

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

cds-question@unistra.frquasarsvisible-astronomyspectroscopyredshiftedline-intensitiesblack-holesradio-sourcesWe perform a systematic search for high-redshift (z>1.5) extreme variability quasars (EVQs) using repeat spectra from the Sixteenth Data Release of the Sloan Digital Sky Survey, which provides a baseline spanning up to ~18yr in the observed frame. We compile a sample of 348 EVQs with a maximum continuum variability at rest frame 1450{AA} of more than 100% (i.e., {delta}V=(Max-Min)/Mean>1). The EVQs show a range of emission-line variability, including 23 where at least one line in our redshift range disappears below detectability, which can then be seen as analogous to low-redshift changing-look quasars (CLQs). Importantly, spurious CLQs caused by problematic SDSS spectral flux calibration, e.g., fiber-drop issue, have been rejected. The similar properties (e.g., continuum/line, difference-composite spectra and Eddington ratio) of normal EVQs and CLQs imply that they are basically the same physical population with analogous intrinsic variability mechanisms, as a tail of a continuous distribution of normal quasar properties. In addition, we find no reliable evidence (<=1{sigma}) to support that CLQs are a subset of EVQs with less efficient accretion. Finally, we also confirm the antibreathing of CIV (i.e., the line width increases as luminosity increases) in EVQs and find that in addition to the ~0.4dex systematic uncertainty in single-epoch CIV virial black hole mass estimates, an extra scatter of ~0.3dex will be introduced by extreme variability.2020ApJ...905...52Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/905/52CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVIII/92 : The FIRST Survey Catalog, Version 2014Dec17 (Helfand+ 2015)V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)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/641/78 : CIV variability in 105 SDSS quasars (Wilhite+, 2006)J/ApJ/679/962 : Quasars with strong nitrogen emission lines (Jiang+, 2008)J/ApJ/680/169 : SDSS DR5 virial black hole masses (Shen+, 2008)J/ApJ/696/870 : Catalina Real-time Transient Survey (CRTS) (Drake+, 2009)J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)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/ApJ/763/32 : Galactic halo RRab stars from CSS (Drake+, 2013)J/ApJ/789/140 : SDSS quasars balmer emission lines (Liu+, 2014)J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)J/ApJS/217/26 : Lick AGN monitoring 2011: light curves (Barth+, 2015)J/ApJS/216/4 : SDSS-RM project: technical overview (Shen+, 2015)J/ApJ/821/33 : Broad H{beta} emission line in Seyfert galaxies (Runco+, 2016)J/ApJ/859/8 : SDSS J120414.37+351800.5 quasar opt. photometry (Liu+, 2018)J/ApJ/854/160 : SDSS&DES long-term extreme variability QSOs (Rumbaugh+, 2018)J/ApJ/874/8 : Follow-up sp. of SDSS changing-look QSOs (Macleod+, 2019)J/ApJS/241/34 : The SDSS Reverberation Mapping (SDSS-RM) project (Shen+, 2019)J/ApJ/883/94 : Optical and UV follow-up of 1ES 1927+654 (Trakhtenbrot+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/905/52https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/905/52http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/905/52https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/905/52https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/905/52http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/905/52GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/905/52/table3 (Catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/905/52/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/905/52/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/905/52/table3?GETtext/xml+votable180.050000true22.900553893.774553890.0055555555555555565/4441 6/42 751 2115-2117 2119 2125 2163-2164 2183 2202-2203 2234 2257 4382 4442 4487 4515 4542 4567 4578 4582 4584 4588-4590 4596 4601 4690 4770 4790 4812-4813 4841 4864 4866 4870 4881 4900 4905 4921 4925 4931-4932 4935 4940 4958-4959 4974-4975 4979 4981 4985-4986 4994 5021 5037 5043 5072 5182-5183 5198 5215-5216 5219 5223 5226 5282 5307 5331 5366 5376 5381 5384 5396 5413 5540 5640 5724 5748 5769 5825 5829 5850 6167 6221 6240 6243 6256 6360 6366 6476 6486 6511 6535 6541 6561 6584 7168 7175 7238 7254 7277 7280 7283 7290 7523 8531 8920 8954 9077 9141 9162 9203 9205 9209 9323 9330 9410 9424 9465-9466 9476 9498 9606 9619 9625 9643 9660 9754 9757 9767 9800 9822 9828 9883 9894 9896-9897 9920 9923 9929 9937 9955 9965 9987 10025 10115 10358 10490 10492 10495 10526 10552 10645 10659 10754 10761 10765 10770 10787 10827 10848 10892 10936 11052 11144 11190 11216 11277 11309 11324 11328 11341 11366 11457 11491 12620 13479 17394 17407 17518 17688 17730 17743 17752-17753 17755 17761-17763 17769 17772-17773 17785 17809 17821 17827 17829 17836 17841-17842 17863 17882 17892 17935 17966 17970 17974-17976 17983 18007 18009 18020-18021 18023-18025 18027 18063-18065 18067 18071 18076 18078-18079 18127 18132 18138 18145 18151 18176 18189-18190 18193 18204 18218 18228 18241-18242 18278 18284 18289 18305 18315 18334 18348 18378 18386 18396 18401 18414 18416 18763 18767 18769 18772 18776 18787 18793 18828-18830 18834 18837-18838 18844 18860 18883 19006 19023 19030 19044 19046 19048-19049 19085 19087 19090-19091 19137 19139 19152 19200 19456 19466 19473 19475 19487 19495 19501 19510 19567 19596 19614 19633 19708 19727 19809 19815 19857 19943 21868 25941 26582 27135 27421 27626 27845 27931 28507 28533 28542 28593 367669.932213363424795e-25 9.932213363424795e-25https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/905/52?format=asciiOpticalRadiodefaultJ/ApJ/905/52/table3Catalogz[1.5/4] Spectroscopic redshiftsrc.redshiftfloatSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGroupID[10859/292717] SDSS DR16 repeat catalog object identifiermeta.idintm_GroupIDNumber of SDSS spectra in this table for this quasarmeta.numberintnullablePlate[309/11703] SDSS spectroscopic plate numbermeta.id;instr.plateintMJD[51792/58543] Modified Julian Date of spectroscopic observationdtime.epochintFiber[2/1000] SDSS spectroscopic fiber numbermeta.number;pos.parallax.spectintRAJ2000Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-8.5/65.6] Declination (J2000)degpos.eq.dec;meta.mainNep[2/23] Number of spectroscopic observationsmeta.numberintNEDNED column added by the CDSmeta.ref.urlcharFIRST[-1/1] FIRST detection code (1=detected; -1=out of FIRST footprint)meta.codeintF1.4GHz[0.7/160]? Observed FIRST 20cm flux densitymJyphot.flux.density;em.radio.750-1500MHzfloatnullableFlag[-1/1] Brightest/faintest epoch flag (1=brightest or -1=faintest epoch)meta.code.errorint1450avg[1/2.1] Rest frame 1450{AA} continuum variability (1)src.var;spect.continuumfloatF1450[-0.007/122] Rest frame 1450{AA} flux density; erg/s/cm^2^/{AA}cW.m**-2.nm**-1phot.fluxfloatSN1450[-0.012/26] Signal-to-Noise at 1450{AA}stat.snrfloatSNCIV[0.1/57.2] Signal-to-Noise of CIV linestat.snrfloatL1350[-1/47.2] Log monochromatic 1350{AA} luminosity; erg/slog(1e-07W)phys.luminosityfloate_L1350[0/0.3]? Uncertainty in L1350log(1e-07W)stat.errorfloatnullableFWHM-civ[1199/13274] Whole CIV line Full-Width at Half-Maximumkm/sspect.line.widthdoublee_FWHM-civ[0.2/7636]? Uncertainty in FWHM-civkm/sstat.errordoublenullableEW-civ[13.6/283.8] Rest frame broad CIV equivalent width; in Angstroms0.1nmspect.line.eqWidthfloate_EW-civ[0/89.6]? Uncertainty in EW-civ0.1nmstat.error;spect.line.eqWidthfloatnullableBH-civ[7.2/9.8]? Log virial BH mass from CIV (2)log(solMass)phys.massfloatnullablee_BH-civ[0.001/1.2]? Uncertainty in BH-civlog(solMass)stat.errorfloatnullableBH-mean[7.4/10]? Log adopted fiducial virial BH mass (3)log(solMass)phys.massfloatnullablee_BH-mean[0.002/1.2]? Uncertainty in BH-meanlog(solMass)stat.errorfloatnullableLogEdd[-2.1/0.3]? Log Eddington ratio based on logMBHaphys.mass;arith.ratiodoublenullablechi2[1.4/33] Reduced {chi}^2^ for CIV line fittingstat.fit.chi2floatType[0/1] Type (0=changing-look quasar (CLQ); 1=extreme variability quasar (EVQ), 650 occurrences)meta.codeintDR16Display data from the SDSS DR16 (V/154) and DR16Q (VII/289) catalogsmeta.ref.urlcharSpInteractive spectrum from SDSS-DR16meta.ref.urlchar