J/ApJ/862/22ivo://CDS.VizieR/J/ApJ/862/22doi:10.26093/cds/vizier.18620022CDSRogerson J.A.Hall P.B.Ahmed N.S.Hidalgo P.R.Brandt W.N.Ak N.F.2020-04-28T13:39:41Z2019-08-28T09:41:45ZCDS support team

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

cds-question@unistra.frquasarsvisible-astronomyspectroscopyredshiftedWe isolate a set of quasars that exhibit emergent CIV broad absorption lines (BALs) in their spectra by comparing spectra in the Sloan Digital Sky Survey (SDSS) Data Release 7 and the SDSS/BOSS Data Releases 9 and 10. After visually defining a set of emergent BALs, follow-up observations were obtained with the Gemini Observatory for 105 quasars. We find an emergence rate consistent with the previously reported disappearance rate of BAL quasars given the relative numbers of non-BAL and BAL quasars in the SDSS. We find that candidate newly emerged BALs are preferentially drawn from among BALs with smaller balnicity indices, shallower depths, larger velocities, and smaller widths. Within two rest-frame years (average) after a BAL has emerged, we find it equally likely to continue increasing in equivalent width in an observation 6 months later (average) as it is to start decreasing. From the time separations between our observations, we conclude that the coherence timescale of BALs is less than 100 rest-frame days. We observe coordinated variability among pairs of troughs in the same quasar, likely due to clouds at different velocities responding to the same changes in ionizing flux, and the coordination is stronger if the velocity separation between the two troughs is smaller. We speculate that the latter effect may be due to clouds having on average lower densities at higher velocities owing to mass conservation in an accelerating flow, causing the absorbing gas in those clouds to respond on different timescales to the same ionizing flux variations.2018ApJ...862...22Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/862/22CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/183 : UBVRI Photometric Standards (Landolt 1992)II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)VII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)VII/270 : SDSS quasar catalog: tenth data release (Paris+, 2014)VII/279 : SDSS quasar catalog: twelfth data release (Paris+, 2017)J/ApJ/641/78 : CIV variability in 105 SDSS quasars (Wilhite+, 2006)J/ApJS/165/1 : BAL QSOs from SDSS DR3 (Trump+, 2006)J/MNRAS/410/860 : Redshift dependence of BAL QSOs (Allen+, 2011)J/A+A/548/A66 : SDSS Quasar Catalog, DR9Q (Paris+, 2012)J/ApJ/763/37 : Metals in SDSS QSOs. I. 1.5<z<4.5 CIV abs. (Cooksey+, 2013)J/ApJ/777/168 : CIV and SiIV broad abs. line troughs in SDSS (Filiz+, 2013)J/ApJ/788/123 : IRTF J-band spectrum of Mrk 231 (Leighly+, 2014)J/MNRAS/454/3962 : 188 CIV BAL QSOs from SDSS DR7 (He+, 2015)J/ApJ/814/150 : Variability of SDSS broad absorption line QSOs (Wang+, 2015)J/ApJ/824/130 : SDSS/BOSS/TDSS CIV BAL quasars (Grier+, 2016)J/ApJS/236/39 : CIV narrow abs. line systems in SDSS-DR14 (Chen+, 2018)J/ApJS/239/23 : CIV NAL systems from SDSS-DR14 quasar spectra (Chen+, 2018)J/A+A/616/A114 : CIV BAL disappearance in SDSS QSOs (De Cicco+, 2018)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/862/22https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/862/22http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/862/22https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/862/22https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/862/22http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/862/22GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/862/22/obs (List of observations and rest-frame time between successive observations of the 105 quasars (tables 3 and 4))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/862/22/obs?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/862/22/obs?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/862/22/obs?GETtext/xml+votable180.050000true0.87579170.1370.0055555555555555566/4096 4138 4194 4218 4492 4665 4865 4868 5055 5337 5504 5508 5804 5834 6219 6502 6916 7175 7332 8382 8417 8756 8760 8827 8925 8939 8991 9058 9155 9270 9380 9431 9609 9613 9741 9758 10277 10283 10494 10551 10611 10765 12380 17662 17672 17768 17773 17840 17982 18078 18087 18090 18171 18833 19209 19388 19426 19434 22001 25597 25849 25953 26012 26044 26093 26173 26237 26257 26289 26339 26351 26402 26481 26496 26503 26530 26563 26571 26582 26974 27059 27084 27086 27303 27333 27378 27468 27497 27500 27574 27658 27673 27745 27790 27792 27854 28025 28054 28657 31450 31468 31531 31674 36783https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/862/22?format=asciiOpticaldefaultJ/ApJ/862/22/obsList of observations and rest-frame time between successive observations of the 105 quasars (tables 3 and 4)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSDSSSDSS DR7 designation (HHMMSS.ss+DDMMSS.s; J2000)meta.id;meta.maincharzspec[1.7/4.2] Spectroscopic redshiftsrc.redshiftfloatSDSS1? Modified Julian Date, SDSS Observation 1dtime.epoch;obsdoublenullableSDSS2? Modified Julian Date, SDSS Observation 2dtime.epoch;obsdoublenullableBOSS1? Modified Julian Date, BOSS Observation 1dtime.epoch;obsdoublenullableBOSS2? Modified Julian Date, BOSS Observation 2dtime.epoch;obsdoublenullableGEM1? Modified Julian Date, Gemini Observation 1dtime.epoch;obsdoublenullableGEM2? Modified Julian Date, Gemini Observation 2dtime.epoch;obsdoublenullableGEM3? Modified Julian Date, Gemini Observation 3dtime.epoch;obsdoublenullableGEM4? Modified Julian Date, Gemini Observation 4dtime.epoch;obsdoublenullableGEM5? Modified Julian Date, Gemini Observation 5dtime.epoch;obsdoublenullabledelta12[2.8/1208]? Rest-frame days between 1st and 2nd observationdtime;arith.difffloatnullabledelta23[1.9/1080]? Rest-frame days between 2nd and 3rd observationdtime;arith.difffloatnullabledelta34[18.7/353]? Rest-frame days between 3rd and 4th observationdtime;arith.difffloatnullabledelta45[6/306.6]? Rest-frame days between 4th and 5th observationdtime;arith.difffloatnullabledelta56[4/37.4]? Rest-frame days between 5th and 6th observationdtime;arith.difffloatnullabledelta67[5.8/10.4]? Rest-frame days between 6th and 7th observationdtime;arith.difffloatnullableSloanDisplay the online SDSS data for the nearest objectmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharNEDNED column added by the CDSmeta.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