J/A+A/622/A29ivo://CDS.VizieR/J/A+A/622/A29doi:10.26093/cds/vizier.36220029CDSMaitra C.Haberl F.Ivanov V.D.Cioni M.-R.L.van Loon J.T.2019-06-27T07:05:21Z2019-06-05T11:43:36ZCDS support team

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

cds-question@unistra.frmagellanic-cloudsquasarsx-ray-sourcesinfrared-sourcesFinding active galactic nuclei (AGN) behind the Magellanic Clouds (MCs) is difficult because of the high stellar density in these fields. Although the first AGN behind the Small Magellanic Cloud (SMC) were reported in the 1980s, it is only recently that the number of AGN known behind the SMC has increased by several orders of magnitude. The mid-infrared colour selection technique has proven to be an efficient means of identifying AGN, especially obscured sources. The X-ray regime is complementary in this regard and we use XMM-Newton observations to support the identification of AGN behind the SMC. We present a catalogue of AGN behind the SMC by correlating an updated X-ray point-source catalogue from our XMM-Newton survey of the SMC with previously identified AGN from the literature as well as a list of candidates obtained from the ALLWISE mid-infrared colour-selection criterion. We studied the properties of the sample with respect to their redshifts, luminosities, and X-ray spectral characteristics. We also identified the near-infrared counterpart of the sources from the VISTA observations. The redshift and luminosity distributions of the sample (where known) indicate that we detect sources ranging from nearby Seyfert galaxies to distant and obscured quasars. The X-ray hardness ratios are compatible with those typically expected for AGN, and the VISTA colours and variability are also consistent with AGN. A positive correlation was observed between the integrated X-ray flux (0.2-12keV) and the ALLWISE and VISTA magnitudes. We further present a sample of new candidate AGN and candidates for obscured AGN. Together these make an interesting subset for further follow-up studies. An initial spectroscopic follow-up of 6 out of the 81 new candidates showed that all six sources are active galaxies, although two have narrow emission lines.2019A&A...622A..29Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/622/A29CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/558/A3 : XMM-Newton point-source catalogue of the SMC (Sturm+, 2013)J/ApJS/221/12 : AGNs in the MIR using AllWISE data (Secrest+, 2015)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/622/A29https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/622/A29http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/622/A29https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/622/A29https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/622/A29http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/622/A29GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/622/A29/tablea1 (Newly identified AGN candidates from the XMM-Newton SMC survey selected using ALLWISE mid-IR colour selection)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/622/A29/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/622/A29/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/622/A29/tablea1?GETtext/xml+votable180.050000true6.3497-71.38960.005555555555555556Cone search capability for table J/A+A/622/A29/tablea4 (Identified candidates for obscured AGN)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/622/A29/tablea4?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/622/A29/tablea4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/622/A29/tablea4?GETtext/xml+votable180.050000true6.3497-71.38960.0055555555555555565/8323 6/32954-32955 33286-33287 33297-33299 33304-33306 33316-33317 33319 33323 33325 33328 33330 33336https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/622/A29?format=asciiX-rayInfrareddefaultJ/A+A/622/A29/tablea1Newly identified AGN candidates from the XMM-Newton SMC survey selected using ALLWISE mid-IR colour selectionrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/81] Candidate sequential numbermeta.recordintNameDesignation (JHHMMSS.ss+DDMMSS.s)meta.id;phys.atmol.configurationcharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainePosPositional errorarcsecstat.error;posfloatXALLWISE source X colour (f12um/f4.6um)phot.color;em.IR;em.IRfloatYALLWISE source Y colour (f4.6um/f3.4um)phot.color;em.IR;em.IRfloatFXX-ray flux in 0.2-12keV band1e-14W.m**-2phot.flux;em.X-rayfloate_FXrms uncertainty on FX1e-14W.m**-2stat.errorfloatY-J? VISTA counterpart Y-J colour indexmagphot.color;em.opt;em.IRfloatnullableJ-Ks? VISTA counterpart J-Ks colour indexmagphot.color;em.IR.J;em.IR.KfloatnullableXMMidXMM designation (JHHMMSS.s+DDMMSS) (G1)meta.idcharJ/A+A/622/A29/tablea4Identified candidates for obscured AGNrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameDesignation (JHHMMSS.ss+DDMMSS.s or NNN.NNNNN.NNN for MACHO sources)meta.id;phys.atmol.configurationcharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainePosPositional errorarcsecstat.error;posfloatFXX-ray flux in 0.2-12keV band1e-14W.m**-2phot.flux;em.X-rayfloate_FXrms uncertainty on FX1e-14W.m**-2stat.errorfloatHR2Hardness ratio 2 (0.5-1.0 keV)phot.flux;arith.ratiofloatHR3Hardness ratio 3 (1.0-2.0 keV)phot.flux;arith.ratiofloatHR4Hardness ratio 4 (2.0-4.5 keV)phot.flux;arith.ratiofloatXMMidXMM designation (JHHMMSS.s+DDMMSS) (G1)meta.idchar