J/A+A/616/A114ivo://CDS.VizieR/J/A+A/616/A114doi:10.26093/cds/vizier.36160114CDSDe Cicco D.Brandt W.N.Grier C.J.Paolillo M.Filiz Ak N.,Schneider D.P.Trump J.R.2019-01-08T08:05:03Z2018-12-12T09:51:22ZCDS support team

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

cds-question@unistra.frquasarsspectroscopyredshiftedline-intensitiesBroad absorption lines (BALs) in the spectra of quasi-stellar objects (QSOs) originate from outflowing winds along our line of sight; winds are thought to originate from the inner regions of the QSO accretion disk, close to the central supermassive black hole (SMBH). These winds likely play a role in galaxy evolution and are responsible for aiding the accretion mechanism onto the SMBH. Several works have shown that BAL equivalent widths can change on typical timescales from months to years; such variability is generally attributed to changes in the covering factor (due to rotation and/or changes in the wind structure) and/or in the ionization level of the gas. We investigate BAL variability, focusing on BAL disappearance. We analyze multi-epoch spectra of more than 1500 QSOs - the largest sample ever used for such a study - observed by different programs from the Sloan Digital Sky Survey-I/II/III (SDSS-I/II/III), and search for disappearing CIV BALs. The spectra cover a rest-frame time baseline ranging from 0.28 to 4.9yr; the source redshifts range from 1.68 to 4.27. We detect 73 disappearing BALs in the spectra of 67 unique sources. This corresponds to 3.9% of BALs disappearing within 4.9yr (rest frame), and 5.1% of our BAL QSOs exhibit at least one disappearing BAL within 4.9yr (rest frame). We estimate the average lifetime of a BAL along our line of sight (~=80-100yr), which appears consistent with the accretion disk orbital time at distances where winds are thought to originate. We inspect various properties of the disappearing BAL sample and compare them to the corresponding properties of our main sample. We also investigate the existence of a correlation in the variability of multiple troughs in the same spectrum, and find it persistent at large velocity offsets between BAL pairs, suggesting that a mechanism extending on a global scale is necessary to explain the phenomenon. We select a more reliable sample of disappearing BALs on the basis of some criteria adopted in a previous publication, where a subset of our current sample was analyzed, and compare the findings from the two works, obtaining generally consistent results.2018A&A...616A.114Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/616/A114CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/252 : SDSS-DR5 quasar catalog (Schneider+, 2007)J/MNRAS/405/2302 : Improved redshifts for SDSS quasar spectra (Hewett+, 2010)J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/616/A114https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/616/A114http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/616/A114https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/616/A114https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/616/A114http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/616/A114GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/616/A114/tablea1 (QSOs in the P4 sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/616/A114/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/616/A114/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/616/A114/tablea1?GETtext/xml+votable180.050000true10.09335940.99436060.0055555555555555566/4354 4815 4934 4958 5063 5363 5368 5564 5584 5676 5807 5861 5914 5931 6644 7261 7277 7446 7480 7495 7525 7568 8913 9234 9387 9433 9613 9777-9778 9901 9933 10492 10548 10572 10698 10721 10861 11042 11208 11345 11439 11779 11846 11873 18114 25911 26023 26383 26407 26550 26571 26594 26988 27003 27045 27290 27293 27303 27351 27659 27813 28181 28622 31408 31420 36778 36812https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/616/A114?format=asciidefaultJ/A+A/616/A114/tablea1QSOs in the P4 samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDSource identification number in this workmeta.id;phys.atmol.numberintSDSSSource SDSS identification (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharzRedshift from Hewett & Wild (2010, Cat. J/MNRAS/405/2302)src.redshiftfloate_zrms uncertainty on zstat.error;src.redshiftfloatimagi-band magnitude from Schneider et al. (2007AJ....134..102S, Cat. VII/252)magphot.mag;em.opt.Ifloate_imagrms uncertainty on imagmagstat.error;phot.mag;em.opt.IfloatiMAGAbsolute i-band magnitude from Shen et al. (2011, Cat. J/ApJS/194/45)magphys.magAbsfloatPMF1Plate-MJD-fiber identifying each SDSS-I/II spectrum where a BAL trough is detectedmeta.idcharNtr1Number of BAL troughs detected in the same spectrummeta.numberintPMF2Plate-MJD-fiber of corresponding BOSS spectrum (MJD>=55176) where disappearance occurs (1)meta.idcharNtr2Number of BAL troughs detected in the same spectrummeta.numberintSp1Interactive spectrum from SDSSmeta.ref.urlcharSp2Interactive spectrum from SDSSmeta.ref.urlcharSimbadSimbad 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.mainJ/A+A/616/A114/tablea2Parameters of disappearing BAL troughsEWRest-frame EW measurement0.1nmspect.line.eqWidthfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDSource identification number in this workmeta.id;phys.atmol.numberintSDSSSource SDSS identification (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharMJDMJD of the SDSS-I/II epoch where the EW of the disappearing BAL trough is measured (1)dtime.epochinte_EWrms uncertainty on EW0.1nmstat.error;spect.line.eqWidthfloatvmaxMaximum velocity of the BAL troughkm/sphys.veloc;stat.maxintvminMinimum velocity of the BAL troughkm/sphys.veloc;stat.minintDTRest-frame {Delta}t between the SDSS-I/II epoch where the BAL trough is detected and the BOSS epoch where disappearance of the same BAL is observeddtime.intervalfloatP8[0/1] BALs belonging to the P8 sample? (2)meta.codecharPP[0/1] BALs belonging to the pristine sample? (2)meta.codechar