J/ApJ/966/85ivo://CDS.VizieR/J/ApJ/966/85CDSZeltyn G.Trakhtenbrot B.Eracleous M.Yang Q.Green P.,Anderson S.F.LaMassa S.Runnoe J.Assef R.J.Bauer F.E.Brandt W.N.,Davis M.C.Frederick S.E.Fries L.B.Graham M.J.Grogin N.A.,Guolo M.Hernandez-Garcia L.Koekemoer A.M.Krumpe M.Liu X.,Martinez-Aldama M.L.Ricci C.Schneider D.P.Shen Y.Sniegowska M.,Temple M.J.Trump J.R.Xue Y.Brownstein J.R.Dwelly T.Morrison S.,Bizyaev D.Pan K.Kollmeier J.A.2026-09-10T08:44:59Z2026-09-10T09:24:46ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiquasarsvisible-astronomyspectroscopyredshiftedblack-holes"Changing-look" active galactic nuclei (CL-AGNs) challenge our basic ideas about the physics of accretion flows and circumnuclear gas around supermassive black holes. Using first-year Sloan Digital Sky Survey V (SDSS-V) repeated spectroscopy of nearly 29,000 previously known active galactic nuclei (AGNs), combined with dedicated follow-up spectroscopy, and publicly available optical light curves, we have identified 116 CL-AGNs where (at least) one broad emission line has essentially (dis-)appeared, as well as 88 other extremely variable systems. Our CL-AGN sample, with 107 newly identified cases, is the largest reported to date, and includes ~0.4% of the AGNs reobserved in first-year SDSS-V operations. Among our CL-AGNs, 67% exhibit dimming while 33% exhibit brightening. Our sample probes extreme AGN spectral variability on months to decades timescales, including some cases of recurring transitions on surprisingly short timescales (<~2 months in the rest frame). We find that CL events are preferentially found in lower-Eddington-ratio (fEdd) systems: Our CL-AGNs have a fEdd distribution that significantly differs from that of a carefully constructed, redshift- and luminosity-matched control sample (Anderson-Darling test yielding p_AD_~6x10^-5^; median fEdd~0.025 versus 0.043). This preference for low fEdd strengthens previous findings of higher CL-AGN incidence at lower fEdd, found in smaller samples. Finally, we show that the broad MgII emission line in our CL-AGN sample tends to vary significantly less than the broad H{beta} emission line. Our large CL-AGN sample demonstrates the advantages and challenges in using multi-epoch spectroscopy from large surveys to study extreme AGN variability and physics.2024ApJ...966...85Zhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/966/85CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)II/328 : AllWISE Data Release (Cutri+ 2013)II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)IX/57 : The Chandra Source Catalog (CSC), Release 2.0 (Evans+, 2019)V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)VII/289 : SDSS quasar catalog, sixteenth data release (DR16Q) (Lyke+, 2020)J/ApJS/166/470 : SDSS-Spitzer type I QSOs IR photometry (Richards+, 2006)J/ApJ/696/870 : Catalina Real-time Transient Survey (CRTS) (Drake+, 2009)J/ApJ/716/530 : Mid-IR variability from the SDWFS (Kozlowski+, 2010)J/ApJ/753/106 : Quasar variability with SDSS & POSS imaging (MacLeod+, 2012)J/A+A/560/A104 : UV variability of quasars (Meusinger+, 2013)J/ApJ/779/109 : Long-term monitoring of NGC 5548 (Peterson+, 2013)J/ApJ/792/30 : NEOWISE magnitudes for near-Earth objects (Mainzer+, 2014)J/ApJS/219/1 : Catalog of Type-1 AGNs from SDSS-DR7 (Oh+, 2015)J/ApJS/216/4 : SDSS-RM project: technical overview (Shen+, 2015)J/MNRAS/463/296 : PanSTARRS-1 slow-blue nuclear hypervar. (Lawrence+, 2016)J/ApJ/854/160 : SDSS and DES long-term extreme var. QSOs (Rumbaugh+, 2018)J/ApJ/852/72 : LFs of tidal disruption flares (van Velzen, 2018)J/ApJ/886/42 : Reverberation mapping & opt. spectra of AGNs (Du+, 2019)J/ApJ/874/8 : Follow-up sp. of SDSS changing-look QSOs (Macleod+, 2019)J/ApJ/886/150 : VRI and K-band light curves of type 1 AGNs (Minezaki+, 2019)J/ApJS/241/34 : SDSS Reverberation Mapping (SDSS-RM) project (Shen+, 2019)J/ApJ/883/94 : Optical & UV follow-up of 1ES 1927+654 (Trakhtenbrot+, 2019)J/ApJ/887/15 : Xinglong sp. of two changing-look SDSS AGNs (Wang+, 2019)J/MNRAS/491/4925 : Changing-state quasars with CRTS (Graham+, 2020)J/ApJ/905/52 : Extreme variability QSOs from SDSS DR16 (Guo+, 2020)J/ApJ/901/55 : SDSS-RM project: MgII lags from 4yrs obs. (Homayouni+, 2020)J/MNRAS/503/2583 : Survey for z< 0.04 CLAGNs (Senarath+, 2021)J/ApJ/933/180 : TDSS. Changing-look quasars candidates (Green+, 2022)J/ApJS/261/5 : BASS. XXV. DR2 AGNs BH masses (Mejia-Restrepo+, 2022)http://irsa.ipac.caltech.edu/Missions/ztf.html : ZTF data on IRSAhttp://www.sdss.org/ : SDSS-V homepagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/966/85https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/966/85http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/966/85https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/966/85https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/966/85http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/966/85GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/966/85/table5 (Robust "Changing-look" active galactic nuclei (CL-AGNs) and extremely variable quasars (EVQs) identified in this work)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/966/85/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/966/85/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/966/85/table5?GETtext/xml+votable180.050000true1.832916725.52461110.005555555555555556Cone search capability for table J/ApJ/966/85/table6 (Spectral measurements of CL-AGNs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/966/85/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/966/85/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/966/85/table6?GETtext/xml+votable180.050000true1.96045830.97088890.005555555555555556Cone search capability for table J/ApJ/966/85/table7 (Follow-up observations for 73 sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/966/85/table7?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/966/85/table7?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/966/85/table7?GETtext/xml+votable180.050000true1.813083326.07038890.0055555555555555565/6823 6826 6/4097 4100 4102 4104 4110 4118 4136 4758 4765 4808-4809 4837 4839 4845 4851 4859 5001 5024 5039 5042 5339 5569 5981 6010 6096 6098 6223 6238 6252 6255 6258 6260 6388 6408-6410 6417 6424 6434 6440 6454-6455 6465 6536 6538 7220 7227 8235 9133 9135 9186 9192 9354 9406 9462 9600 9610 9612 9622 9822 9874 9937 9940 9986-9987 10029 10032 10112 10149 10153 10501 10508 10515 10560 10747 10982 10999 11033 11092 11195 11253 11424 11426 11432 11434 11521 11776-11777 11805-11807 11850 12630 12637 13320 17406 17663 17689 17702 17709 17711 17715 17721 17725 17743 17746-17747 17749 17751 17753-17755 17764 17767 17773 17778 17807 17819 17827 17834 17836 17840 17983 18001 18003 18006-18007 18011 18026 18065 18070 18076 18078 18086 18092 18094-18095 18176 18406 18416 18769 18775 18778 18781 18800 19021 19023 19032 19034 19089 19097-19100 19122 19458 19941 20122 20182 20188 20251 20254 21849 21852-21853 21886-21887 25982 26069-26070 26073 26076 26586 27258 27289-27291 27298-27299 27302 27308 27327 27345 27363 27370-27371 28079 28156 28369 28405 28492 28580-28581 28583 28588 31065https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/966/85?format=asciiOpticaldefaultJ/ApJ/966/85/table5Robust "Changing-look" active galactic nuclei (CL-AGNs) and extremely variable quasars (EVQs) identified in this workrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCLspectral measurements available for this CL-AGN (link to Table 6)meta.codecharNameSDSS Identifier (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharprimaryz[0.058/2.8] Redshiftsrc.redshiftdoubleFirst[51782/58523] Modified Julian Date of earliest spectrumdtime.epochintLast[59146/59387] Modified Julian Date of last spectrumdtime.epochintClassEvent type (1)src.classcharCHa[-19/6.7]? Ha emission line change parameter (2)arith.ratio;phot.flux;stat.errorfloatnullableCHb[-1578/6]? Hb emission line change parameter (2)arith.ratio;phot.flux;stat.errordoublenullableCMgII[-34/8.6]? MgII emission line change parameter (2)arith.ratio;phot.flux;stat.errorfloatnullableCCIII[-6.8/5.6]? CCIII emission line change parameter (2)arith.ratio;phot.flux;stat.errorfloatnullableCCIV[1.7/6.7]? CCIV emission line change parameter (2)arith.ratio;phot.flux;stat.errorfloatnullableSpec[0/2]? Ancillary spectroscopy (3)meta.codeintnullableOpt[1/2] Ancillary optical photometry (4)meta.codeintWISE[0/2]? Ancillary WISE data (5)meta.codeintnullableNotesReferences (6)meta.notecharspNumber of follow-up sp. measurements for this source (link to Table 7)meta.numberintnullableSloanDisplay the online SDSS-DR19 data for the nearest objectmeta.ref.urlchar_RAPositions from SDSS names (right ascension part)degpos.eq.ra;meta.main_DEPositions from SDSS names (declination part)degpos.eq.dec;meta.mainJ/ApJ/966/85/table6Spectral measurements of CL-AGNsNameSDSS Identifier (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharlogL[40.7/45.3] Luminosity used for mass estimate (Ha or MgII at 3000{AA})phys.luminosityfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintz[0.058/2.4] Redshiftsrc.redshiftdoubleSpComEmission line complex which spectral measurement are based on ("Ha" or "MgII")meta.id;spect.linecharFWHM[1475/34793] Emission line FWHMkm/sspect.line.width;spect.lineintlogMBH[6.38/9.5] Estimated black hole masslog(solMass)phys.massfloatlogLbol[42.6/46] Bolometric luminosity (1)log(1e-07W)phys.luminosity;phot.flux.bolfloatlogfEdd[-2.75/-0.33] Eddington ratiophys.luminosity;arith.ratiofloat_RAPositions from SDSS names (right ascension part)degpos.eq.ra;meta.main_DEPositions from SDSS names (declination part)degpos.eq.dec;meta.mainJ/ApJ/966/85/table7Follow-up observations for 73 sourcesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSDSS Identifier (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharObsFacility where spectrum was taken (1)meta.id;instr.obstycharMJD[59329/60088] Modified Julian Date of the epoch of the spectrumdtime.epochintRSource also available in the robust sample (link to Table 5)meta.ref.urlintnullableSloanDisplay the online SDSS-DR19 data for the nearest objectmeta.ref.urlchar_RAPositions from SDSS names (right ascension part)degpos.eq.ra;meta.main_DEPositions from SDSS names (declination part)degpos.eq.dec;meta.main