J/ApJ/900/79ivo://CDS.VizieR/J/ApJ/900/79doi:10.26093/cds/vizier.19000079CDSHou M.Li Z.Liu X.2022-03-21T09:29:38Z2022-01-12T12:48:07ZCDS support team

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

cds-question@unistra.fractive-galactic-nucleiredshiftedvisible-astronomyx-ray-sourcessurveysWe present a Chandra archival study of optically selected active galactic nucleus (AGN) pairs at a median redshift z~0.1. Out of 1286 AGN pairs (with projected separations rp<100kpc and velocity offsets {Delta}v<600km/s) optically identified from the Sloan Digital Sky Survey Seventh Data Release, we find 67 systems with archival Chandra observations, which represents the largest sample of optically selected AGN pairs studied in the X-ray. Among the 67 AGN pairs, 21 systems have both nuclei detected in the X-ray, 36 have one nucleus detected in the X-ray, and 10 have no X-ray detection. The X-ray detection rate, 78/134=58% (+/-7% 1{sigma} Poisson errors), is significantly higher than that (23/134=17%+/-4%) of a comparison sample of star-forming galaxy pairs, lending support to the optical AGN classification. In the conservative case where X-ray contamination from star formation is removed, the X-ray detection rate becomes 27%+/-4%, consistent with predictions from the latest galaxy merger simulations. The 2-10keV X-ray luminosity L2-10keV increases with decreasing projected separation in AGN pairs for rp>~15kpc, suggesting an enhancement of black hole accretion even in early-stage mergers. On the other hand, L2-10keV appears to decrease with decreasing projected separation at rp<~15kpc, which is contradictory to predictions from merger simulations. The apparent decrease in L2-10 keV of AGN pairs at rp<~15kpc may be caused by (i) enhanced absorbing columns from merger-induced gas inflows, (ii) feedback effects from early-stage mergers, and/or (iii) small number statistics. Future X-ray studies with larger samples are needed to put our results on firmer statistical ground.2020ApJ...900...79Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/900/79CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 1999-2014)II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)J/AJ/129/2138 : Centers of early-type galaxies with HST (Lauer+, 2005)J/AJ/131/1 : Binary quasars in the SDSS (Hennawi+, 2006)J/AJ/131/2766 : Quasar luminosity function from SDSS-DR3 (Richards+, 2006)J/ApJ/678/635 : Spectroscopy of quasar binary candidates (Myers+, 2008)J/ApJS/182/216 : Surface photometry of Virgo ellipticals (Kormendy+, 2009)J/ApJ/719/1672 : SDSS binary quasars at high redshift. I. (Hennawi+, 2010)J/ApJ/737/101 : AGN pairs from SDSS-DR7. I. (Liu+, 2011)J/ApJS/201/23 : Spectroscopy of 88 z<0.7 SDSS QSOs (Eracleous+, 2012)J/ApJ/746/L22 : Dual AGNs in the nearby Universe (Koss+, 2012)J/AJ/144/125 : Photometry & spectroscopy of Markarian 266 (Mazzarella+, 2012)J/ApJ/789/140 : SDSS quasars balmer emission lines (Liu+, 2014)J/A+A/578/A110 : Isolated galaxies, pairs & triplets (Argudo-Fernandez+, 2015)J/MNRAS/453/1562 : CRTS close supermassive black hole binaries (Graham+, 2015)J/ApJ/876/53 : Chandra X-ray point sources in the Fornax cluster (Jin+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/900/79https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/900/79http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/900/79https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/900/79https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/900/79http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/900/79GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/900/79/table1 (Information of AGN pairs with Chandra observation)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/900/79/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/900/79/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/900/79/table1?GETtext/xml+votable180.050000true222.74879-0.037560.005555555555555556Cone search capability for table J/ApJ/900/79/table2 (X-ray properties of AGN pairs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/900/79/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/900/79/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/900/79/table2?GETtext/xml+votable180.050000true222.7489-0.037570.0055555555555555566/1701 1712 4344 4350 4835 4966 5015 5040 5236 5437 5664 5996 6225 7223 8194 8268 8288 8526 8659 8832 8843 8887 9009 9150 9830 10323 10358 10379 10413 10512 10518 10752 10847 11029 11405 11424 17237 17252 17840 18009 18027 18096 19044-19045 19050 19457 21887 21977 23217 25855 25942 26005 26298 26351 26493 26581 27318 27414 27420 27617 27646 27719 27801 28188 31461 49019https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/900/79?format=asciiX-rayOpticaldefaultJ/ApJ/900/79/table1Information of AGN pairs with Chandra observationSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSDSSIdentifier (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharprimaryRAJ2000Right Ascension (J2000) (1)degpos.eq.ra;meta.mainDEJ2000Declination (J2000) (1)degpos.eq.dec;meta.mainz[0.02/0.2] Spectroscopic redshift from Liu+ 2011, J/ApJ/737/101src.redshiftfloatrp[2.3/99] Projected physical separation of AGN pairkpcpos.angDistancefloatlogM*[8.8/11.4]? log stellar masslog(solMass)phys.massfloatnullableFOIII[5/4902]? The [OIII] emission line flux; 10^-17^erg/s/cm^2^1e-17mW.m**-2phot.fluxfloatnullablee_FOIII[1/35]? The 1{sigma} uncertainty in FOIII1e-17mW.m**-2stat.errorfloatnullableSFR[-1/17.4] Star Formation Rate (2)solMass/yrphys.SFRfloatE_SFR[0/45] Upper uncertainty in SFRsolMass/yrstat.error;stat.maxfloate_SFR[0/16] Lower uncertainty in SFRsolMass/yrstat.error;phys.SFRfloatObsID[868/20466] Chandra observation identifiermeta.id;obs.param;obsintf_ObsID[*] Flag on ObsID (3)meta.codecharExp[1.7/592.2] Exposure timekstime.duration;obs.exposurefloatlogLX[39.38/42.05] log 0.5-8keV limiting X-ray luminosity for source detection; erg/slog(1e-07W)phys.luminosity;em.X-rayfloatFlag[0/1] Detection flag (1=detection)meta.code.errorintSloanDisplay the online SDSS-DR7 data for the nearest objectmeta.ref.urlcharNEDNED column added by the CDSmeta.ref.urlcharJ/ApJ/900/79/table2X-ray properties of AGN pairsl_F2-8Limit flag on F2-8meta.code.errorcharRAJ2000Right Ascension (J2000) (2)degpos.eq.ra;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSDSSIdentifier (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharDEJ2000Declination (J2000) (2)degpos.eq.dec;meta.mainl_CtsLimit flag on Ctsmeta.code.errorcharCts[2/3836] Observed net counts in 0.5-8keV bandctphot.count;em.X-rayfloatE_Cts[2/66]? Upper uncertainty in Ctsctstat.error;stat.maxfloatnullablee_Cts[1/65]? Lower uncertainty in Ctsctstat.errorfloatnullablel_F0.5-2Limit flag on F0.5-2meta.code.errorcharF0.5-2[0.2/289] Observed 0.5-2keV photon flux1e-06ph.cm**-2.s**-1phot.flux;em.X-ray.softfloatE_F0.5-2[0.1/12]? Upper uncertainty in F0.5-21e-06ph.cm**-2.s**-1stat.error;stat.maxfloatnullablee_F0.5-2[0.08/12]? Lower uncertainty in F0.5-21e-06ph.cm**-2.s**-1stat.errorfloatnullableF2-8[0.16/364] Observed 2-8keV photon flux1e-06ph.cm**-2.s**-1phot.flux;em.X-ray.hardfloatE_F2-8[0.07/8]? Upper uncertainty in F2-81e-06ph.cm**-2.s**-1stat.error;stat.maxfloatnullablee_F2-8[0.05/8]? Lower uncertainty in F2-81e-06ph.cm**-2.s**-1stat.errorfloatnullablel_logL0.5-2Limit flag on logL0.5-2meta.code.errorcharlogL0.5-2[39.3/43.6] Log 0.5-2keV unabsorbed luminositylog(1e-07W)phys.luminosity;em.X-rayfloatE_logL0.5-2[0.01/0.3]? Upper uncertainty in logL0.5-2log(1e-07W)stat.error;stat.maxfloatnullablee_logL0.5-2[0.01/0.5]? Lower uncertainty in logL0.5-2log(1e-07W)stat.errorfloatnullablel_logL2-10Limit flag on logL2-10meta.code.errorcharlogL2-10[39.5/44] Log 2-8keV unabsorbed luminositylog(1e-07W)phys.luminosity;em.X-rayfloatE_logL2-10[0.01/0.3]? Upper uncertainty in logL2-10log(1e-07W)stat.error;stat.maxfloatnullablee_logL2-10[0.01/0.4]? Lower uncertainty in logL2-10log(1e-07W)stat.errorfloatnullableHR[-0.96/0.96] Hardness ratio (3)phot.flux;arith.ratiofloatE_HR[0/0.6] Upper uncertainty in HRstat.error;stat.maxfloate_HR[0.01/0.61] Lower uncertainty in HRstat.errorfloat