J/A+A/645/A95ivo://CDS.VizieR/J/A+A/645/A95doi:10.26093/cds/vizier.36450095CDSHasinger G.Freyberg M.Hu E.M.Waters C.Z.Capak P.Moneti A.,McCracken H.J.2021-06-18T13:50:41Z2021-01-19T07:19:57ZCDS support team

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

cds-question@unistra.frsurveysx-ray-sourcesactive-galactic-nucleigalaxy-clustersinfrared-sourcesvisible-astronomyThe North-Ecliptic Pole is an important region for extragalactic surveys. Deep/wide contiguous surveys are being performed by several space observatories. We analyse all ROSAT pointed and survey observations within 40deg^2^ around the NEP, restricting the field-of-view to the inner 30' radius. We obtain an X-ray catalogue of 805 sources with 0.5-2keV fluxes >2.9*10^-15^erg/cm^2^/s, a factor of three deeper than the ROSAT All-Sky Survey in this field. The sensitivity and angular resolution of our data are comparable to the eROSITA All-Sky Survey expectations. The 50% position error radius of the sample of X-ray sources is ~10". We use HEROES optical and near-infrared imaging photometry from Subaru and CFHT telescopes together with literature catalogues and a new deep and wide Spitzer survey in the field to identify X-ray sources and calculate photometric redshifts for the candidate counterparts. In particular we utilize mid-IR colours to identify AGN X-ray counterparts. Despite relatively large error circles and faint counterparts, confusion and systematic errors, we obtain a rather reliable catalogue of 766 optical counterparts, redshifts and optical classifications. We find a new population of luminous absorbed X-ray AGN at large redshifts, not recognized in previous X-ray surveys, but identified in our work due to the unique combination of survey solid angle, X-ray sensitivity and multiwavelength photometry. We also use the WISE and Spitzer photometry to identify a sample of 185 AGN selected purely through mid-IR colours, most of which are not detected by ROSAT. Their redshifts and upper limits to X-ray luminosity and X-ray-to-optical flux ratios are even higher than for the new class of X-ray selected luminous type 2 AGN (AGN2); they are probably a natural extension of this sample. This unique dataset is important as a reference sample for future deep surveys in the NEP region, in particular for eROSITA and also for Euclid and SPHEREX. We predict that most of the absorbed distant AGN should be readily picked up by eROSITA, but they require sensitive mid-IR imaging to be recognized as optical counterparts.2021A&A...645A..95Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/645/A95CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/617/192 : ROSAT AGN Catalog in North Ecliptic Pole (Mullis+, 2004)J/ApJS/162/304 : ROSAT NEP X-ray source catalog (Henry+, 2006)J/A+A/461/977 : Rosat North Ecliptic survey stellar population (Micela+, 2007)J/A+A/588/A103 : Second ROSAT all-sky survey (2RXS) source cataloghttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/645/A95https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/645/A95http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/645/A95https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/645/A95https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/645/A95http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/645/A95GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/645/A95/table1 (ROSAT NEP raster X-ray catalogue)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/645/A95/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/645/A95/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/645/A95/table1?GETtext/xml+votable180.050000true261.472285668.15910080.005555555555555556Cone search capability for table J/A+A/645/A95/table3 (ROSAT NEP candidate optical ID catalogue)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/645/A95/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/645/A95/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/645/A95/table3?GETtext/xml+votable180.050000true261.475000968.161217740.005555555555555556Cone search capability for table J/A+A/645/A95/table4 (AGN candidates selected by mid-IR colours)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/645/A95/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/645/A95/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/645/A95/table4?GETtext/xml+votable180.050000true264.520964166.912846110.0055555555555555565/2559 2901 2903 3839 4010-4011 4014 6/10229-10231 10235 11601 11603 11609 11611 11633 11635-11638 11641 15350-15351 15353-15355 16034-16035 16038-16039 16050-16051 16054https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/645/A95?format=asciiX-rayOpticalInfrareddefaultJ/A+A/645/A95/table1ROSAT NEP raster X-ray cataloguerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintXID[1/805] Internal X-ray identification numbermeta.id;meta.mainintRAXX-ray right ascension (J2000.0)degpos.eq.ra;meta.mainDEXX-ray declination (J2000.0)degpos.eq.dec;meta.mainePosXX-ray position errorarcsecstat.error;posfloatMLExistence maximum likelihood (threshold 11)stat.likelihoodfloatCTSNet X-ray source countsctphot.count;em.X-rayfloate_CTSError on net source countsctstat.errorfloatXMLExtent maximum likelihoodstat.likelihood;phys.angSizefloatExpTimeExposure timestime.duration;obs.exposureintFX0.5-2 keV X-ray flux (1)1e-17W.m**-2phot.flux;em.X-rayfloatFlagM[0/1] Manual parameter determination flagmeta.code.errorintJ/A+A/645/A95/table3ROSAT NEP candidate optical ID catalogueQQuality of redshift (4)meta.code.qual;src.redshiftcharFX/FOX-ray to optical flux ratiophot.flux;arith.ratiofloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintXIDInternal X-ray identification numbermeta.id;meta.mainintm_XID[abcd] letters for multiple counterpartsmeta.code.multipcharRAOOptical counterpart right ascension (J2000.0)degpos.eq.ra;meta.mainDEOOptical counterpart declination (J2000.0)degpos.eq.dec;meta.mainmagOptOptical AB magnitude in r_mag Bandmagphot.mag;em.optfloatr_magOpt[GPSirz] Source of the optical magnitude/coordinates (1)meta.ref;pos.framecharmagIR? Infrared AB magnitude in r_magIR bandmagphot.mag;em.opt.Ifloatnullabler_magIR[Wi] Source of the infrared magnitude (2)meta.ref;pos.framecharCI1-2? Mid-infrared colour WISE W1-W2 or IRAC I1-I2phot.color;em.IR;em.IRfloatnullableClassOptical counterpart ID class (3)meta.code.classintz? Redshiftsrc.redshiftfloatnullablelogLX? log (0.5-2keV luminosity), in erg/s unitlog(1e-07W)phys.luminosity;em.X-rayfloatnullableIDQ[0/2] Identification quality (5)meta.code.qualintComNotes on individual objectsmeta.notecharJ/A+A/645/A95/table4AGN candidates selected by mid-IR coloursrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAIMid-IR AGN candidate right ascension (J2000.0)degpos.eq.ra;meta.mainDEIMid-IR AGN candidate declination (J2000.0)degpos.eq.dec;meta.mainmagOptOptical AB Magnitudemagphot.mag;em.optfloatI1magIRAC I1 AB magnitudemagphot.mag;em.IR.3-4umfloatI1-I2Mid-infrared colour IRAC I1-I2magphot.color;em.IR;em.IRfloate_I1-I2Error of mid-IR colourmagstat.errorfloatClass[1/2] Mid-IR AGN candidate ID class (1)meta.code.classintzphPhotometric redshiftsrc.redshiftfloatMLExistence maximum likelihoodstat.likelihoodfloatuCTSNet X-ray source count upper limitctphot.count;em.X-rayfloatExpTimeExposure timestime.duration;obs.exposureintuFXUpper limit to 0.5-2 keV X-ray flux (2)1e-17W.m**-2phot.flux;em.X-rayfloatuFX/FOUpper limit to X-ray to optical flux ratiophot.flux;stat.maxfloatulogLXUpper limit log (0.5-2 keV luminosity) in erg/s unitlog(1e-07W)phys.luminosity;em.X-rayfloat