J/MNRAS/453/1562ivo://CDS.VizieR/J/MNRAS/453/1562doi:10.26093/cds/vizier.74531562CDSGraham M.J.Djorgovski S.G.Stern D.Drake A.J.Mahabal A.A.,Donalek C.Glikman E.Larson S.Christensen E.2024-08-15T20:15:06Z2016-04-01T14:52:58ZCDS support team

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

cds-question@unistra.frquasarsstellar-massesHierarchical assembly models predict a population of supermassive black hole (SMBH) binaries. These are not resolvable by direct imaging but may be detectable via periodic variability (or nanohertz frequency gravitational waves). Following our detection of a 5.2-year periodic signal in the quasar PG 1302-102, we present a novel analysis of the optical variability of 243 500 known spectroscopically confirmed quasars using data from the Catalina Real-time Transient Survey (CRTS) to look for close (<0.1pc) SMBH systems. Looking for a strong Keplerian periodic signal with at least 1.5 cycles over a baseline of nine years, we find a sample of 111 candidate objects. This is in conservative agreement with theoretical predictions from models of binary SMBH populations. Simulated data sets, assuming stochastic variability, also produce no equivalent candidates implying a low likelihood of spurious detections. The periodicity seen is likely attributable to either jet precession, warped accretion discs or periodic accretion associated with a close SMBH binary system. We also consider how other SMBH binary candidates in the literature appear in CRTS data and show that none of these are equivalent to the identified objects. Finally, the distribution of objects found is consistent with that expected from a gravitational-wave-driven population. This implies that circumbinary gas is present at small orbital radii and is being perturbed by the black holes. None of the sources is expected to merge within at least the next century. This study opens a new unique window to study a population of close SMBH binaries that must exist according to our current understanding of galaxy and SMBH evolution.2015MNRAS.453.1562Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/453/1562CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/453/1562https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/453/1562http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/453/1562https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/453/1562https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/453/1562http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/453/1562GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/453/1562/table2 (The 111 periodic quasar candidates meeting the selection criteria)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/453/1562/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/453/1562/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/453/1562/table2?GETtext/xml+votable180.050000true3.0454167-1.36877780.0055555555555555566/4400 4510 4705 4734 4753 4813 4827 4863 5078 5198 5203 5386 5657 5671 5673 5861 5932 6028 6064 6237 6398 6434 6497 6519 6615 7300 7377 7558 8196 8293 8321 8332 8348 8363 8419 8512 8545 8590 8764 8871-8872 8954 9229 9248 9305 9393 9503 9517 9644 9656 9709 10162 10202 10373 10457 12631 17757 17822 18081 18097 18390 19382 19413 22009 22535 23353 23485 25684 25742 25986 26013 26100 26287 26315 26356 26495 26500 26515 26592 26613 26615 26621 26923 27415 27470 27643 27740 27857 27878 27887 27918 27922 27979 28067 28098 28110 28434 28452 28545 28548 28552 31416 31436 31462 31651 32451 35906 36075 46995 48483https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/453/1562?format=asciidefaultJ/MNRAS/453/1562/table2The 111 periodic quasar candidates meeting the selection criteriaSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameNamemeta.id;meta.maincharRAJ2000Rigth ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainzRedshiftsrc.redshiftfloatVmedMedian V magnitudemagphot.mag;em.opt.VfloatPerPerioddtime.periodintlogMBH? Black hole mass (1)log(solMass)phys.massfloatnullabler? Separation (2)pcpos.distance;phys.sizefloatnullabletinsp? Rest-frame merger time (2)yrtime.epochdoublenullableDtGW? Maximum induced timing residual amplitude (2)nsstat.fit.residual;src.var.amplitude;stat.maxfloatnullableLCName of the file with light curve in subdirectory imagesmeta.id;meta.filechar