J/MNRAS/457/110ivo://CDS.VizieR/J/MNRAS/457/110doi:10.26093/cds/vizier.74570110CDSMenzel M.-L.Merloni A.Georgakakis A.Salvato M.Aubourg E.,Brandt W.N.Brusa M.Buchner J.Dwelly T.Nandra K.Paris I.,Petitjean P.Schwope A.2024-08-15T20:17:49Z2016-12-02T14:19:58ZCDS support team

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

cds-question@unistra.frsurveysactive-galactic-nucleix-ray-sourcesvisible-astronomysloan-photometryinfrared-photometryThis paper presents a survey of X-ray-selected active galactic nuclei (AGNs) with optical spectroscopic follow-up in a ~18deg^2^ area of the equatorial XMM-XXL north field. A sample of 8445 point-like X-ray sources detected by XMM-Newton above a limiting flux of F_0.5-10keV_>10^-15^erg/cm2/s was matched to optical (Sloan Digital Sky Survey, SDSS) and infrared (IR; WISE) counterparts. We followed up 3042 sources brighter than r=22.5mag with the SDSS Baryon Oscillation Spectroscopic Survey (BOSS) spectrograph. The spectra yielded a reliable redshift measurement for 2578 AGNs in the redshift range z=0.02-5.0, with 0.5-2keV luminosities ranging from 10^39^-10^46^erg/s. This is currently the largest published spectroscopic sample of X-ray-selected AGNs in a contiguous area. The BOSS spectra of AGN candidates show a distribution of optical line widths which is clearly bimodal, allowing an efficient separation between broad- and narrow-emission line AGNs. The former dominate our sample (70 per cent) due to the relatively bright X-ray flux limit and the optical BOSS magnitude limit. We classify the narrow-emission line objects (22 per cent of the full sample) using standard optical emission line diagnostics: the majority have line ratios indicating the dominant source of ionization is the AGN. A small number (8 per cent of the full sample) exhibit the typical narrow line ratios of star-forming galaxies, or only have absorption lines in their spectra. We term the latter two classes 'elusive' AGN, which would not be easy to identify correctly without their X-ray emission. We also compare X-ray (XMM-Newton), optical colour (SDSS) and and IR (WISE) AGN selections in this field. X-ray observations reveal, by far, the largest number of AGN. The overlap between the selections, which is a strong function of the imaging depth in a given band, is also remarkably small. We show using spectral stacking that a large fraction of the X-ray AGNs would not be selectable via optical or IR colours due to host galaxy contamination. A substantial fraction of AGN may therefore be missed by these longer wavelength selection methods.2016MNRAS.457..110Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/457/110CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIX/49 : XXL Survey: First results (Pierre+, 2016)J/MNRAS/459/1602 : AGN sample in the northern XMM-XXL field (Liu+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/457/110https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/457/110http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/457/110https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/457/110https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/457/110http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/457/110GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/457/110/catalog (Catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/457/110/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/457/110/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/457/110/catalog?GETtext/xml+votable180.050000true30.009-5.154550.0055555555555555565/4419 4421-4425 4428 6/17503 17525 17527 17671 17674-17675 17681-17683 17704-17705 17708-17709 17716-17717 17728 177302.040811542443644e-19 6.090060298487514e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/457/110?format=asciiX-rayOpticalInfrareddefaultJ/MNRAS/457/110/catalogCatalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintUXIDUXID (1)meta.id;meta.maincharRAXXMM Right ascension (J2000) (RA_XMM) (1)degpos.eq.ra;meta.mainDEXXMM Declination (J2000) (DEC_XMM) (1)degpos.eq.dec;meta.maine_RAXError RA-and Declination (RADECERR_XMM) (1)degstat.errorfloatFfull? Full X-ray flux 0.5-10keV (FLUX_FULL) (1)mW.m**-2phot.flux;em.X-raydoublenullableFsoft? Soft X-ray flux 0.5-2keV (FLUX_SOFT) (1)mW.m**-2phot.flux;em.X-raydoublenullableFhard? Hard X-ray flux 2-10keV (FLUX_HARD) (1)mW.m**-2phot.flux;em.X-raydoublenullableLfull? Full X-ray luminosity 0.5-10keV (LUM_FULL) (1)1e-07Wphys.luminosity;em.X-raydoublenullableLsoft? Soft X-ray luminosity 0.5-2keV (LUM_SOFT) (1)1e-07Wphys.luminosity;em.X-raydoublenullableLhard? Hard X-ray luminosity 2-10keV (LUM_HARD) (1)1e-07Wphys.luminosity;em.X-raydoublenullableOBJIDSDSS-ID from SDSS DR-8meta.idcharRASdeg? SDSS DR8 Right ascension (J2000) (RA_SDSS)degpos.eq.ranullableDESdeg? SDSS DR8 Declination (J2000) (DEC_SDSS)degpos.eq.ranullablee_RASdeg? Error for Right ascension from SDSS DR8 (RAERR_SDSS)degstat.errordoublenullablee_DESdeg? Error Declination from SDSS DR8 (DECERR_SDSS)degstat.errordoublenullableLRXS? Likelihood-Ratio of the matching with SDSS counterpart (LR_XMMSDSS) (2)stat.likelihooddoublenullableumag? Psf-magnitude for u band from SDSS DR8 (AB) (PSF_MAG_U)magphot.mag;em.opt.Ufloatnullablegmag? Psf-magnitude for g band from SDSS DR8 (AB) (PSF_MAG_G)magphot.mag;em.opt.Bfloatnullablermag? Psf-magnitude for r band from SDSS DR8 (AB) (PSF_MAG_R)magphot.mag;em.opt.Rfloatnullableimag? Psf-magnitude for i band from SDSS DR8 (AB) (PSF_MAG_I)magphot.mag;em.opt.Ifloatnullablezmag? Psf-magnitude for z band from SDSS DR8 (AB) (PSF_MAG_Z)magphot.mag;em.opt.Ifloatnullablee_umag? Error on umag (AB) (PSFERR_MAG_U)magstat.error;phot.mag;em.opt.Udoublenullablee_gmag? Error on gmag (AB) (PSFERR_MAG_G)magstat.error;phot.mag;em.opt.Bfloatnullablee_rmag? Error on rmag (AB) (PSFERR_MAG_R)magstat.error;phot.mag;em.opt.Rfloatnullablee_imag? Error on imag (AB) (PSFERR_MAG_I)magstat.error;phot.mag;em.opt.Ifloatnullablee_zmag? Error on zmag (AB) (PSFERR_MAG_Z)magstat.error;phot.mag;em.opt.Ifloatnullableumod? Model-magnitudes for u band from SDSS DR8 (AB) (MODEL_MAG_U)magphot.mag;meta.modelledfloatnullablegmod? Model-magnitudes for g band from SDSS DR8 (AB) (MODEL_MAG_G)magphot.mag;meta.modelledfloatnullablermod? Model-magnitudes for r band from SDSS DR8 (AB) (MODEL_MAG_R)magphot.mag;meta.modelledfloatnullableimod? Model-magnitudes for i band from SDSS DR8 (AB) (MODEL_MAG_I)magphot.mag;meta.modelledfloatnullablezmod? Model-magnitudes for z band from SDSS DR8 (AB) (MODEL_MAG_Z)magphot.mag;meta.modelledfloatnullablee_umod? Error for umod (MODELERR_MAG_U)magstat.errorfloatnullablee_gmod? Error for gmod (MODELERR_MAG_G)magstat.errorfloatnullablee_rmod? Error for rmod (MODELERR_MAG_R)magstat.errorfloatnullablee_imod? Error for imod (MODELERR_MAG_I)magstat.errorfloatnullablee_zmod? Error for zmod (MODELERR_MAG_Z)magstat.errorfloatnullableType[3/6]? Optical morphology (4)src.morph.typeintnullablePQSOsum? Summed XDQSO QSO probability from Bovy et al. (2011ApJ...729..141B) (PQSOSUM)stat.fit.goodnessfloatnullableGood[0/2]? BOSS good flag from Bovy et al. (2011ApJ...729..141B) (GOOD)meta.codeintnullableWISEDesignation from allWISE (JHHMMSS.ss+DDMMSS.s) (WISE_DESIGN)meta.idcharRAWdeg? allWISE Right ascension (J2000) (RA_WISE)degpos.eq.ranullableDEWdeg? allWISE Declination (J2000) (DEC_WISE)degpos.eq.ranullablee_RAWdeg? One-sigma uncertainty for Right ascension from allWISE (RASIG_WISE)degstat.errorfloatnullablee_DEWdeg? One-sigma uncertainty for Declination from allWISE (DECSIG_WISE)degstat.errorfloatnullableLRXW? Likelihood-Ratio of the matching with WISE counterpart (Georgakakis et al., 2011MNRAS.414..992G) (LR_XMMWISE) (3)stat.likelihooddoublenullableW1mag? Mpro-magnitude of W1 band from allWISE (Vega) (MPRO_MAG_W1)magphot.mag;em.IR.3-4umfloatnullableW2mag? Mpro-magnitude of W2 band from allWISE (Vega) (MPRO_MAG_W2)magphot.mag;em.IR.4-8umfloatnullableW3mag? Mpro-magnitude of W3 band from allWISE (Vega) (MPRO_MAG_W3)magphot.flux.density;em.IR.8-15umfloatnullableW4mag? Mpro-magnitude of W4 band from allWISE (Vega) (MPRO_MAG_W4)magphot.flux.density;em.IR.15-30umfloatnullablee_W1mag? Profile-fit photometric measurement uncertainty for W1 band from allWISE (Vega) (MPROSIG_MAG_W1)magstat.error;phot.magfloatnullablee_W2mag? Profile-fit photometric measurement uncertainty for W2 band from allWISE (Vega) (MPROSIG_MAG_W2)magstat.error;phot.magfloatnullablee_W3mag? Profile-fit photometric measurement uncertainty for W3 band from allWISE (Vega) (MPROSIG_MAG_W3)magstat.error;phot.magfloatnullablee_W4mag? Profile-fit photometric measurement uncertainty for W4 band from allWISE (Vega) (MPROSIG_MAG_W4)magstat.error;phot.magfloatnullableClean[0/1]? Exclusion of diffraction spikes, halos, optical ghosts and blended sources (CLEAN) (5)meta.codeintnullablePlate? BOSS plate number (PLATE)meta.id;instr.plateintnullableFiber? BOSS fibre-ID number (FIBERID)meta.idintnullableMJD? BOSS MJD (MJD)time.epochintnullablezBoss? Redshift from the automatic BOSS pipeline (Z_BOSS)src.redshift;pos.heliocentricdoublenullablee_zBoss[-6/29]? Error for Z_BOSS (ZERR_BOSS)stat.errordoublenullablezwarning? Redshift warning flag from the automatic BOSS pipeline (ZWARNING)meta.codeintnullableSNmedall? Average S/N ratio of all five SDSS bands from the automatic BOSS pipeline (SN_MEDIAN_ALL)stat.snrfloatnullablez? Redshift after visual inspection and refit of spectrum with spreduce1d.pro (Z)src.redshiftdoublenullablee_z[-6/4]? Error for Z (ZERR)stat.error;src.redshiftdoublenullableq_z[1/30]? Redshift confidence flag from visual inspection (Z_CONF) (6)meta.code.qual;src.redshiftintnullableClassClassification for q_z=3 spectra (CLASS) (7)meta.codecharSt/BLStar/BL Lac classification (STAR/BLLAC)meta.code.class;src.classchar