J/ApJ/799/72ivo://CDS.VizieR/J/ApJ/799/72doi:10.26093/cds/vizier.17990072CDSFu H.Myers A.D.Djorgovski S.G.Yan L.Wrobel J.M.Stockton A.2017-06-22T14:28:48Z2015-07-06T09:17:31ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiradio-continuum-emissionvisible-astronomysloan-photometryredshiftedGalaxy mergers play an important role in the growth of galaxies and their supermassive black holes. Simulations suggest that tidal interactions could enhance black hole accretion, which can be tested by the fraction of binary active galactic nuclei (AGNs) among galaxy mergers. However, determining the fraction requires a statistical sample of binaries. We have identified kiloparsec-scale binary AGNs directly from high-resolution radio imaging. Inside the 92deg^2^ covered by the high-resolution Very Large Array survey of the Sloan Digital Sky Survey (SDSS) Stripe 82 field, we identified 22 grade A and 30 grade B candidates of binary radio AGNs with angular separations less than 5" (10kpc at z=0.1). Eight of the candidates have optical spectra for both components from the SDSS spectroscopic surveys and our Keck program. Two grade B candidates are projected pairs, but the remaining six candidates are all compelling cases of binary AGNs based on either emission line ratios or the excess in radio power compared to the H{alpha}-traced star formation rate. Only two of the six binaries were previously discovered by an optical spectroscopic search. Based on these results, we estimate that ~60% of our binary candidates would be confirmed once we obtain complete spectroscopic information. We conclude that wide-area high-resolution radio surveys offer an efficient method to identify large samples of binary AGNs. These radio-selected binary AGNs complement binaries identified at other wavelengths and are useful for understanding the triggering mechanisms of black hole accretion.2015ApJ...799...72Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/799/72CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/260 : The SDSS-DR7 quasar catalog (Schneider+, 2010)VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)J/MNRAS/441/1802 : Low-redshift QSOs in SDSS Stripe 82 (Karhunen+, 2014)J/MNRAS/436/3581 : X-ray observations of Stripe 82 (LaMassa+, 2013)J/ApJ/753/42 : Double-peaked AGN. I. Dual AGN candidates (Comerford+, 2012)J/ApJ/746/L22 : Dual AGNs in the nearby Universe (Koss+, 2012)J/A+A/525/A37 : Variability index of QSOs in SDSS Stripe 82 (Meusinger+, 2011)J/ApJ/737/101 : AGN pairs from SDSS-DR7. I. (Liu+, 2011)J/ApJ/716/866 : SDSS search for binary AGN (Smith+, 2010)J/ApJ/708/427 : Type 2 AGNs with double-peaked [OIII] lines (Liu+, 2010)J/ApJ/705/L76 : AGNs with double-peaked [OIII] lines (Wang+, 2009)J/ApJ/690/20 : Models of the AGN and black hole populations (Shankar+, 2009)J/A+A/487/993 : MAMBO Mapping of c2d Clouds and Cores (Kauffmann+, 2008)J/MNRAS/362/9 : Radio-loud AGN in SDSS (Best+, 2005)J/ApJ/554/803 : New VLA Sky Survey (NVSS) Cat of IRAS 2 Jy Galaxies (Yun+ 2001)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/799/72https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/799/72http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/799/72https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/799/72https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/799/72http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/799/72GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/799/72/AGN (Grade A and B candidate binary radio AGNs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/799/72/AGN?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/799/72/AGN?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/799/72/AGN?GETtext/xml+votable180.050000true11.15554171.02569440.0055555555555555566/17661 17662 17807 17811 17812 17825 17828 17829 17830 17832 17834 17835 17998 18001 18010 18014 18024 18025 18027 18069 18112 18178 18180 18749 18795 18832 18833 18838 18839 18841 18843 18853 18854 18858 18859 18860 18861 18880 19029 19031 19034 19035 19036 19037 19045 190569.276497240453405e-25 6.090060298487514e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/799/72?format=asciiRadioOpticaldefaultJ/ApJ/799/72/AGNGrade A and B candidate binary radio AGNsPairDisplay the data of the pairmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintQGrade of the candidate binary (See Note (3) of table 3)meta.code.qualcharSpDisplay the spectroscopic data of this source in a confirmed pairmeta.ref.urlcharRNameRadio designation (HHMMSS.ss+DDMMSS.s; J2000)meta.id;meta.maincharprimaryS1.4pk[0.3/23.2] 1.4GHz peak flux density (in mJy/beam)mJyphot.flux.density;em.radio.750-1500MHzfloate_S1.4pk[0.05/0.8] S1.4pk uncertaintymJystat.errorfloatS1.4int[0.3/43.5] 1.4GHz integrated flux densitymJyphot.flux.density;em.radio.750-1500MHzfloatONameOptical designation of the counterpart (HHMMSS.ss+DDMMSS.s; J2000)meta.id.crosscharSep[1.6/6] Angular separation between the optical counterparts in the pairarcsecpos.angDistancefloatumag[17.5/28.1]? SDSS u-band Petrosian AB magnitudemagphot.mag;em.opt.Ufloatnullablegmag[15.7/25.7]? SDSS g-band Petrosian AB magnitudemagphot.mag;em.opt.Bfloatnullablermag[14.8/25.5]? SDSS r-band Petrosian AB magnitudemagphot.mag;em.opt.Rfloatnullableimag[14.2/25.5]? SDSS i-band Petrosian AB magnitudemagphot.mag;em.opt.Ifloatnullablezmag[14/23.6]? SDSS z-band Petrosian AB magnitudemagphot.mag;em.opt.Ifloatnullablez[0.04/1]? Spectroscopic redshiftsrc.redshiftfloatnullableInstInstrument used to obtained the spectroscopic redshift (SDSS, BOSS or LRIS)instr.setupcharSloanDisplay the online SDSS data for the nearest objectmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RAJ2000 coordinate of the optical source (right ascension part)degpos.eq.ra;meta.main_DEJ2000 coordinate of the optical source (declination part)degpos.eq.dec;meta.mainJ/ApJ/799/72/table3*Properties of spectroscopically confirmed pairsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRNameRadio designation (HHMMSS.ss+DDMMSS.s; J2000)meta.id;meta.maincharQ[AB] Grade of the candidate binary (1)meta.code.qualcharz[0.04/0.4] Spectroscopic redshiftsrc.redshiftfloatInstInstrument used to obtained z: LRIS or SDSSinstr.setupcharaSep[2.5/4.6] Angular separation between the optical counterparts in the pairarcsecpos.angDistancefloatpSep[4.1/12] Projected separation in kiloparsecskpcpos.distancefloatDelV[20.9/137] Radial velocity separation {Delta}Vkm/sphys.veloc;arith.difffloatlogP1.4[22/25] Logarithmic radio power computed from the integrated source flux density at 1.4GHzlog(W.Hz**-1)phys.luminosity;em.radio;meta.modelledfloatl_logLHaLimit flag on logLHameta.code.errorcharlogLHa[39.4/42.4] Log H{alpha} luminosity in erg/s; corrected for reddening and aperture-losslog(1e-07W)phys.luminosity;em.line.HalphafloatEWHa[-3/51] H{alpha} equivalent width in the observed frame in {AA}0.1nmspect.line.eqWidth;em.line.Halpha;obs.fieldfloate_EWHa[0.1/1.2] EWHa uncertainty0.1nmstat.errorfloat[NII]/Ha[0.5/1.7]? [NII]{lambda}6584/H{alpha} line flux ratiophot.flux;arith.ratio;spect.linefloatnullablee_[NII]/Ha[0.1/0.4]? The 1{sigma} error on [NII]/Hastat.errorfloatnullable[OIII]/Hb[0.3/1.3]? [OIII]{lambda}5007/H{beta} line flux ratiophot.flux;em.line.OIII;arith.ratiofloatnullablee_[OIII]/Hb[0.1/0.7]? The 1{sigma} error on [OIII]/Hbstat.errorfloatnullableRcl"Excess" or "Normal" Radio classification (2)src.classcharBPTcl"Comp" or "AGN2" classification based on the BPT line-ratio diagram in Figure 6 (3)src.classchar