J/ApJ/949/49ivo://CDS.VizieR/J/ApJ/949/49doi:10.26093/cds/vizier/ba-xn-1hCDSHe L.Hou M.Li Z.Feng S.Liu X.2026-07-02T11:59:17Z2025-07-23T13:25:33ZCDS support team

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

cds-question@unistra.frinteracting-galaxiesactive-galactic-nucleiredshiftedvisible-astronomyx-ray-sourcesblack-holesHigh-resolution X-ray observations offer a unique tool for probing the still-elusive connection between galaxy mergers and active galactic nuclei (AGNs). We present an analysis of nuclear X-ray emission in an optically selected sample of 92 close galaxy pairs (with projected separations <~20kpc and line-of-sight velocity offsets <500km/s) at low redshift (\bar{z}~0.07), based on archival Chandra observations. The parent sample of galaxy pairs is constructed without imposing an optical classification of nuclear activity, thus it is largely free of selection effect for or against the presence of an AGN. Nor is this sample biased for or against gas-rich mergers. An X-ray source is detected in 70 of the 184 nuclei, giving a detection rate of 38%_-5%_^+5%^, down to a 0.5-8keV limiting luminosity of <~10^40^erg/s. The detected and undetected nuclei show no systematic difference in their host galaxy properties such as galaxy morphology, stellar mass, and stellar velocity dispersion. When potential contamination from star formation is avoided (i.e., L_2-10keV_>10^41^erg/s), the detection rate becomes 18%_-3%_^+3%^ (32/184), which shows no excess compared to the X-ray detection rate of a comparison sample of optically classified single AGNs. The fraction of pairs containing dual AGN is only 2%_-2%_^+2%^. Moreover, most nuclei at the smallest projected separations probed by our sample (a few kiloparsecs) have an unexpectedly low apparent X-ray luminosity and Eddington ratio, which cannot be solely explained by circumnuclear obscuration. These findings suggest that close galaxy interaction is not a sufficient condition for triggering a high level of AGN activity.2023ApJ...949...49Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/949/49CatalogResearchIsServedByTAP 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/156 : LAMOST DR7 catalogs (Luo+, 2019)J/ApJ/705/L76 : AGNs with double-peaked [OIII] lines (Wang+, 2009)J/ApJ/737/101 : AGN pairs from SDSS-DR7. I. (Liu+, 2011)J/ApJ/746/L22 : Dual AGNs in the nearby Universe (Koss+, 2012)J/MNRAS/419/2095 : HMXBs in nearby galaxies (Mineo+, 2012)J/ApJ/764/41 : X-ray binary evolution across cosmic time (Fragos+, 2013)J/ApJ/799/72 : Binary AGNs from the VLA Stripe 82 survey (Fu+, 2015)J/other/RAA/16.C7 : LAMOST-SDSS galaxy pairs (Shen+, 2016)J/ApJ/836/99 : NuSTAR serendipitous survey: 40-month cat (Lansbury+, 2017)J/ApJ/869/171 : Chandra observations of NuSTAR sources (Tomsick+, 2018)J/MNRAS/474/3875 : Galaxy And Mass Assembly (GAMA): DR3 (Baldry+, 2018)J/ApJ/900/79 : Chandra obs. of SDSS AGN pairs at z_med_~0.1 (Hou+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/949/49https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/949/49http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/949/49https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/949/49https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/949/49http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/949/49GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/949/49/table1 (Information of close galaxy pairs with Chandra observation)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/949/49/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/949/49/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/949/49/table1?GETtext/xml+votable180.050000true156.7516717.816940.005555555555555556Cone search capability for table J/ApJ/949/49/table2 (X-ray properties of close galaxy pairs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/949/49/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/949/49/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/949/49/table2?GETtext/xml+votable180.050000true156.752317.816920.0055555555555555566/4097 4300 4349-4350 4352 4577 4649 4990 5040 5046 5116 5236 5334 5370 5395 5483 5530 5781 5930 5989 5996 6013 6084 6086 6092 6115 7208 7223 7228 7503 8220 8222 8230 8693 8787 8832 8843 8919 8970 9145 9150 9242 9443 9895 10144 10311 10313 10378 10413 10484 10512 10696 10878 10954 11029 11591 11792 17214 18008 18096 18114 18841 19050 19457 21853 21873 22396 25855 25952 26005 26097 26102 26142 26209 26305 26493 26563 26581 26962 26984 27350 27361 27646 27654 27722 27731 27742 27801 27857 27936 27962https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/949/49?format=asciiX-rayOpticaldefaultJ/ApJ/949/49/table1Information of close galaxy pairs with Chandra observationrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSimbadSimbad column added by the CDSmeta.ref.urlcharNEDNED column added by the CDSmeta.ref.urlcharRAJ2000Right Ascension (J2000) (1)degpos.eq.ra;meta.mainDEJ2000[-10.3/65.2] Declination (J2000) (1)degpos.eq.dec;meta.mainz[0.017/0.18] Spectroscopic redshiftsrc.redshiftfloatrp[3/19.7] Projected physical separation of galaxy pairskpcpos.angDistancefloatlogMs[7.1/11.8]? log stellar masslog(solMass)phys.massfloatnullableSFR[0/50]? Star Formation Rate (2)solMass/yrphys.SFRfloatnullableE_SFR[0/74.3]? Upper uncertainty in SFRsolMass/yrstat.error;stat.max;phys.SFRfloatnullablee_SFR[0/32]? Lower uncertainty in SFRsolMass/yrstat.error;stat.min;phys.SFRfloatnullablelogMBH[5.6/8.9]? log black hole mass (3)log(solMass)phys.massfloatnullablelogLX[39.2/42.9] log 0.5-8keV limiting X-ray luminositylog(1e-07W)phys.luminosity;em.X-rayfloatFlag[0/1] X-ray detection flag (1=X-ray detection)meta.code.errorintSloanDisplay the online SDSS-DR17 data for the nearest objectmeta.ref.urlcharSDSSSDSS name (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharprimaryJ/ApJ/949/49/table2X-ray properties of close galaxy pairsSDSSSDSS name (JHHMMSS.ss+DDMMSS.s)meta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension (J2000) (1)degpos.eq.ra;meta.mainDEJ2000[-10.3/65.2] Declination (J2000) (1)degpos.eq.dec;meta.mainCts[2/5274] Observed net counts in 0.5-8keV bandsctphot.count;em.X-rayfloatE_Cts[2/77] Upper uncertainty in Ctsctstat.error;stat.max;phot.countfloate_Cts[1.3/76] Lower uncertainty in Ctsctstat.error;stat.min;phot.countfloatl_F0.5-2Limit flag on F0.5-2meta.code.error;phot.flux;em.X-raycharF0.5-2[0.26/786] Observed 0.5-2keV photon flux1e-06ph.cm**-2.s**-1phot.flux;em.X-ray.softfloatE_F0.5-2[0.1/35]? Upper uncertainty in F0.5-21e-06ph.cm**-2.s**-1stat.error;stat.max;phot.fluxfloatnullablee_F0.5-2[0.1/28]? Lower uncertainty in F0.5-21e-06ph.cm**-2.s**-1stat.error;stat.min;phot.fluxfloatnullablel_F2-8Limit flag on F2-8meta.code.error;phot.flux;em.X-raycharF2-8[0.1/636] Observed 2-8keV photon flux1e-06ph.cm**-2.s**-1phot.flux;em.X-ray.mediumfloatE_F2-8[0.05/37]? Upper uncertainty in F2-81e-06ph.cm**-2.s**-1stat.error;stat.max;phot.fluxfloatnullablee_F2-8[0.05/28.4]? Lower uncertainty in F2-81e-06ph.cm**-2.s**-1stat.error;stat.min;phot.fluxfloatnullablel_logL0.5-2Limit flag on logL0.5-2meta.code.error;phys.luminosity;em.X-ray.softcharlogL0.5-2[38.9/42.8] Log 0.5-2keV unabsorbed luminosity; erg/slog(1e-07W)phys.luminosity;em.X-ray.softfloatE_logL0.5-2[0.01/0.5]? Upper uncertainty in logL0.5-2log(1e-07W)stat.error;stat.max;phys.luminosityfloatnullablee_logL0.5-2[0.01/0.9]? Lower uncertainty in logL0.5-2log(1e-07W)stat.error;stat.min;phys.luminosityfloatnullablel_logL2-10Limit flag on logL2-10meta.code.error;phys.luminosity;em.X-ray.mediumcharlogL2-10[39.2/43.9] Log 2-10keV unabsorbed luminosity; erg/slog(1e-07W)phys.luminosity;em.X-ray.mediumfloatE_logL2-10[0.01/0.5]? Upper uncertainty in logL2-10log(1e-07W)stat.error;stat.max;phys.luminosityfloatnullablee_logL2-10[0.01/1.6]? Lower uncertainty in logL2-10log(1e-07W)stat.error;stat.min;phys.luminosityfloatnullableHR[-0.95/0.97] Hardness ratio (2)phot.flux;arith.ratio;em.X-rayfloatE_HR[0/0.8] Upper uncertainty in HRstat.error;stat.max;phot.fluxfloate_HR[0.01/0.8] Lower uncertainty in HRstat.error;stat.min;phot.fluxfloat