J/A+A/469/27ivo://CDS.VizieR/J/A+A/469/27doi:10.26093/cds/vizier.34690027CDSCarrera F.J.Ebrer J.Mateos S.Ceballos M.T.Corral A.Barcons X.,Page M.J.Rosen S.R.Watson M.G.Tedds J.A.Della Ceca R.Maccacaro T.,Brunner H.Freyberg M.Lamer G.Bauer F.E.Ueda Y.2007-08-19T10:59:06Z2007-08-19T10:54:31ZCDS support team

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

cds-question@unistra.frsurveysx-ray-sourcesRecent results have revised upwards the total X-ray background (XRB) intensity below 10keV, therefore an accurate determination of the source counts is needed. There are also contradictory results on the clustering of X-ray selected sources. We have studied the X-ray source counts in four energy bands: soft (0.5-2keV), hard (2-10keV), XID (0.5-4.5keV) and ultra-hard (4.5-7.5keV) in order to evaluate the contribution of sources at different fluxes to the X-ray background. We have also studied the angular clustering of X-ray sources in those bands. AXIS (An XMM International Survey) is a survey of 36 high Galactic latitude XMM observations covering 4.8deg^2^ in the Northern sky and containing 1433 serendipitous X-ray sources detected with 5-sigma significance. This survey has similar depth to the XMM catalogues and therefore serves as a pathfinder to explore their possibilities. We have combined this survey with shallower and deeper surveys, and fitted the source counts with a Maximum Likelihood technique. Using only AXIS sources we have studied the angular correlation using a novel robust technique. Our source counts results are compatible with most previous samples in the soft, XID, ultra-hard and hard bands. We have improved on previous results in the hard band. The fractions of the XRB resolved in the surveys used in this work are 87%, 85%, 60% and 25% in the soft, hard, XID and ultra-hard bands, respectively. Extrapolation of our source counts to zero flux is not sufficient to saturate the XRB intensity. Only galaxies and/or absorbed AGN could contribute the remaining unresolved XRB intensity. Our results are compatible, within the errors, with recent revisions of the XRB intensity in the soft and hard bands. The maximum fractional contribution to the XRB comes from fluxes within about a decade of the break in the source counts (~10^-14^cgs), reaching ~50% of the total in the soft and hard bands. Angular clustering (widely distributed over the sky and not confined to a few deep fields) is detected at 99-99.9% significance in the soft and XID bands, with no detection in the hard and ultra-hard band (probably due to the smaller number of sources). We cannot confirm the detection of significantly stronger clustering in the hard-spectrum hard sources. Medium depth surveys such as AXIS are essential to determine the evolution of the X-ray emission in the Universe below 10keV.2007A&A...469...27Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/469/27CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIX/37 : XMM-Newton Serendipitous Source Catalogue, 1XMM (XMM-SSC, 2003)J/A+A/428/383 : XMM-Newton Bright Serendipitous Survey (Della Ceca+, 2004)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/469/27https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/469/27http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/469/27https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/469/27https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/469/27http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/469/27GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/469/27/table1 (Basic XMM-Newton field data)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/469/27/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/469/27/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/469/27/table1?GETtext/xml+votable180.050000true0.12625-25.1250.005555555555555556Cone search capability for table J/A+A/469/27/table23 (Counts, spectral information and fluxes of the sources (tables 2 and 3))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/469/27/table23?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/469/27/table23?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/469/27/table23?GETtext/xml+votable180.050000true0.00442-25.173408890.0055555555555555565/1967 6/206 5090-5091 5312-5313 5857 5860 7969 8066-8067 8072-8073 10255 10266 10464-10465 11253 11255 11936 11938 12024-12025 16591 17074-17075 17593 17595-17596 17598 17688 17690-17691 18206-18207 18639 18661 19017 19019-19020 19848-19849 20071 20460 24896 24898 24949 24951 25634 25680 25682 26561 26563 28149 28151 28583 28589 31628 31630 44892 44894 48423 48434 48478-48479 48500-48501 48610 48614 48616https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/469/27?format=asciiX-raydefaultJ/A+A/469/27/table1Basic XMM-Newton field datarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintTargetTarget of the XMM-Newton observationobs.param;obscharOBSIDXMM-Newton revolution/Observation IDmeta.id;meta.maincharRAJ2000Right ascension of the field center (J2000)pos.eq.ra;meta.mainDEJ2000Declination of the field center (J2000)pos.eq.dec;meta.mainExpTimeXMM-Newton pn exposure timestime.duration;obs.exposurefloatFilterXMM-Newton pn filter namemeta.id;instr.filtercharNHGalGalactic column density1e+20cm**-2phys.columnDensity;pos.galacticfloatRAt? Right ascension of the target exclusionpos.eq.ranullableDEt? Declination of the target exclusionpos.eq.decnullablexr.tExclusion radius around the targetarcsecinstr.saturationintxwWidth excluded around the OOOT events striparcsecinstr.saturationintRAa? Right ascension of the additional exclusionpos.eq.ranullableDEa? Declination of the additional exclusionpos.eq.decnullablexr.aRadius of the additional exclusionarcsecinstr.saturationintJ/A+A/469/27/table23Counts, spectral information and fluxes of the sources (tables 2 and 3)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintXMMUIAU name of the source, hhmmss.s+ddmmssmeta.id;meta.maincharRAJ2000Right Ascension J2000degpos.eq.ra;meta.mainDEJ2000Declination J2000degpos.eq.dec;meta.mainePos90% uncertainty radius in positionarcsecstat.errorfloatCR2Countrate in 0.5-2keV bandct/sphot.count;em.X-rayfloate_CR2Uncertainty in that bandct/sstat.errorfloatML2Likelihood of detection in that bandstat.likelihooddoubleCR3Countrate in 2-4.5keV bandct/sphot.count;em.X-rayfloate_CR3Uncertainty in that bandct/sstat.errorfloatML3Likelihood of detection in that bandstat.likelihooddoubleCR4Countrate in 4.5-7.5keV bandct/sphot.count;em.X-rayfloate_CR4Uncertainty in that bandct/sstat.errorfloatML4Likelihood of detection in that bandstat.likelihoodfloatCR5Countrate in 7.5-12keV bandct/sphot.count;em.X-rayfloate_CR5Uncertainty in that bandct/sstat.errorfloatML5Likelihood of detection in that bandstat.likelihoodfloatCRXIDCountrate in 0.5-4.5keV bandct/sphot.count;em.X-rayfloate_CRXIDUncertainty in that bandct/sstat.errorfloatMLXIDLikelihood of detection in that bandstat.likelihooddoubleGsoft? Photon index in 0.5-4.5keVspect.indexfloatnullableE_Gsoft? Upper 1sigma uncertainty on GSoftstat.error;stat.maxfloatnullablee_Gsoft? Lower 1sigma uncertainty on GSoftstat.errorfloatnullableFsoft? Flux in the 0.5-2keV band (Soft)mW.m**-2phot.flux;em.X-ray.softdoublenullablee_Fsoft? 1sigma uncertainty on FSoftmW.m**-2stat.errordoublenullableGhard? Photon index in 2-12keVspect.indexfloatnullableE_Ghard? Upper 1sigma uncertainty on GHardstat.error;stat.maxfloatnullablee_Ghard? Lower 1sigma uncertainty on GHardstat.errorfloatnullableFhard? Flux in the 2-10keV band (Hard)mW.m**-2phot.flux;em.X-ray.mediumdoublenullablee_Fhard? 1sigma uncertainty on FHardmW.m**-2stat.errordoublenullableFXID? Flux in the 0.5-4.5keV band (XID)mW.m**-2phot.flux;em.X-ray.mediumdoublenullablee_FXID? 1sigma uncertainty on FXIDmW.m**-2stat.errordoublenullableFUH? Flux in the 4.5-7.5keV band (UH)mW.m**-2phot.flux;em.X-ray.mediumdoublenullablee_FUH? 1sigma uncertainty on FUHmW.m**-2stat.errordoublenullableG0510? Photon index in 0.5-12keVspect.indexfloatnullableE_G0510? Upper 1sigma uncertainty on G0510stat.error;stat.maxfloatnullablee_G0510? Lower 1sigma uncertainty on G0510stat.errorfloatnullableF0510? Flux in the 0.5-10keV bandmW.m**-2phot.flux;em.X-ray.mediumdoublenullablee_F0510? 1sigma uncertainty on F0510mW.m**-2stat.errordoublenullablesS[0/1] 1 = belongs to the Soft samplemeta.noteintsH[0/1] 1 = belongs to the Hard samplemeta.noteintsX[0/1] 1 = belongs to the XID samplemeta.noteintsU[0/1] 1 = belongs to the UH samplemeta.noteint