J/A+A/469/1211ivo://CDS.VizieR/J/A+A/469/1211doi:10.26093/cds/vizier.34691211CDSTrevese D.Vagnetti F.Puccetti S.Fiore F.Tomei M.Bershady M.A.2017-10-16T14:57:28Z2008-04-13T12:50:51ZCDS support team

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

cds-question@unistra.frsurveysx-ray-sourcesThe maximum number density of Active Galactic Nuclei (AGNs), as deduced from X-ray studies, occurs at z>=1, with lower luminosity objects peaking at smaller redshifts. Optical studies lead to a different evolutionary behaviour, with a number density peaking at z~2 independently of the intrinsic luminosity, but this result is limited to active nuclei brighter than the host galaxy. A selection based on optical variability can detect low luminosity AGNs (LLAGNs), where the host galaxy light prevents the identification by non-stellar colours. We want to collect X-ray data in a field where it exists an optically-selected sample of "variable galaxies", i.e. variable objects with diffuse appearance, to investigate the X-ray and optical properties of the population of AGNs, particularly of low luminosity ones, where the host galaxy is visible. We observed a field of ~0.2{deg}^2^ in the Selected Area 57, for 67ks with XMM-Newton. We detected X-ray sources, and we correlated the list with a photographic survey of SA 57, complete to B_J_~23 and with available spectroscopic data. We obtained a catalogue of 140 X-ray sources to limiting fluxes 5x10^-16^, 2x10^-15^erg/cm^2^/s in the 0.5-2keV and 2-10keV respectively, 98 of which are identified in the optical bands. The X-ray detection of part of the variability-selected candidates confirms their AGN nature. Diffuse variable objects populate the low luminosity side of the sample. Only 25/44 optically-selected QSOs are detected in X-rays. 15% of all QSOs in the field have X/O<0.1.2007A&A...469.1211Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/469/1211CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/469/1211https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/469/1211http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/469/1211https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/469/1211https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/469/1211http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/469/1211GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/469/1211/table2 (The source catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/469/1211/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/469/1211/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/469/1211/table2?GETtext/xml+votable180.050000true197.046458329.18066670.005555555555555556Cone search capability for table J/A+A/469/1211/table3 (Optical identifications)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/469/1211/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/469/1211/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/469/1211/table3?GETtext/xml+votable180.050000true197.236083329.19969440.0055555555555555566/10383https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/469/1211?format=asciiX-raydefaultJ/A+A/469/1211/table2The source catalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintOSimbad column added by the CDSmeta.ref.urlcharSA57Xcatalog numbermeta.id;meta.mainintprimaryf_SA57X[cd] Flag on source detection (1)meta.codecharRAJ2000X-ray right ascension (J2000)pos.eq.ra;meta.mainDEJ2000X-ray declination (J2000)pos.eq.dec;meta.mainFxt0.5-10keV flux (10-14erg/cm2/s)1e-17W.m**-2phot.flux;em.X-rayfloatf_Fxt[bu] Note on 0.5-10keV detection (2)meta.codecharFxs0.5-2keV flux (10-14erg/cm2/s)1e-17W.m**-2phot.flux;em.X-rayfloatf_Fxs[bu] Note on 0.5-2keV detection (2)meta.codecharFxh2-10keV flux (10-14erg/cm2/s)1e-17W.m**-2phot.flux;em.X-rayfloatf_Fxh[bu] Note on 2-10keV detection (2)meta.codecharIDrrank of optical identification (G1)meta.code.qualcharJ/A+A/469/1211/table3Optical identificationsz? redshiftsrc.redshiftfloatnullableClassclassification (2)src.classcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSA57XSA57X number, as in table1.meta.id;meta.mainintIDrrank of optical identification (1)meta.code.qualcharNserkpno survey of SA 57 optical catalog number (1)meta.idintn_Nser[d] d: Number in NGPFG Catalogue (Infante et al., 1995, Cat. VII/208, NGPFG NNNNN in Simbad)meta.notecharRAJ2000right ascension (J2000)pos.eq.ra;meta.mainDEJ2000declination (J2000)pos.eq.dec;meta.mainBjmagKPNO Bj magnitudemagphot.mag;em.opt.BfloatFmag? KPNO F magnitudemagphot.mag;em.opt.Rfloatnullablen_Class[e] e: Candidates or confirmed AGNs selected through variability and not previously selected by other methodsmeta.notechar