J/ApJ/596/944ivo://CDS.VizieR/J/ApJ/596/944doi:10.26093/cds/vizier.15960944CDSHarrison F.A.Eckart M.E.Mao P.H.Helfand D.J.Stern D.2008-02-09T14:23:52Z2008-02-09T15:22:59ZCDS support team

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

cds-question@unistra.frsurveysx-ray-sourcesThe Serendipitous Extragalactic X-Ray Source Identification (SEXSI) program is designed to extend greatly the sample of identified extragalactic hard X-ray (2-10keV) sources at intermediate fluxes (~10^-13^ to 10^-15^erg/cm^2^/s). SEXSI, which studies sources selected from more than 2deg^2^, provides an essential complement to the Chandra Deep Fields, which reach depths of 5x10^-16^erg/cm^2^/s (2-10keV) but over a total area of less than 0.2deg^2^. In this paper we describe the characteristics of the survey and our X-ray data analysis methodology. We present the cumulative flux distribution for the X-ray sample of 1034 hard sources and discuss the distribution of spectral hardness ratios. Our logN-logS in this intermediate flux range connects to those found in the Deep Fields, and by combining the data sets, we constrain the hard X-ray population over the flux range in which the differential number counts change slope and from which the bulk of the 2-10keV X-ray background arises. We further investigate the logN-logS distribution separately for soft and hard sources in our sample, finding that while a clear change in slope is seen for the softer sample, the hardest sources are well described by a single power law down to the faintest fluxes, consistent with the notion that they lie at lower average redshift.2003ApJ...596..944Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/596/944CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 2002)J/AJ/122/2810 : Chandra Deep Field North Survey. 1Ms catalog (Brandt+, 2001)J/AJ/126/539 : Chandra Deep Fields North & South. 2Ms Cat. (Alexander+, 2003)J/ApJS/139/369 : Chandra Deep Field South. 1Ms catalog (Giacconi+, 2002)J/ApJS/156/35 : SEXSI catalog. II (Eckart+, 2005)J/ApJS/165/19 : SEXSI catalog. III (Eckart+, 2006)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/596/944https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/596/944http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/596/944https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/596/944https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/596/944http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/596/944GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/596/944/table2 (Chandra observations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/596/944/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/596/944/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/596/944/table2?GETtext/xml+votable180.050000true35.637542.349170.005555555555555556Cone search capability for table J/ApJ/596/944/table4 (Source catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/596/944/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/596/944/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/596/944/table4?GETtext/xml+votable180.050000true35.427791742.44836110.005555555555555556Cone search capability for table J/ApJ/596/944/table6 (Soft-band only source catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/596/944/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/596/944/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/596/944/table6?GETtext/xml+votable180.050000true35.190833342.33172220.005555555555555556Chandra6/13 24 1128 1129 2388 2389 2390 2409 2411 3383 3389 6495 7178 7273 8268 9272 10037 10080 10338 10344 10345 10386 10387 10583 10589 10743 10760 10761 10888 11460 11461 11605 11632 11634 11791 11802 16276 18780 18782 18878 19217 19220 22959 22970 25769 28479 49125 49127https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/596/944?format=asciiX-raydefaultJ/ApJ/596/944/table2Chandra observationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalaxyTarget galaxy namemeta.id.parentcharMTypeMorphological typesrc.morph.typecharz? Redshiftsrc.redshiftfloatnullablecz? Heliocentric velocitykm/sspect.dopplerVeloc;pos.heliocentricintnullableRAJ2000Right ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Declination (J2000.0)pos.eq.dec;meta.mainNHGalactic hydrogen column density1e+20cm**-2phys.columnDensity;pos.galacticfloatExpTimeExposure time (Total: 1648ks)kstime.duration;obs.exposureintChipsACIS chips (Total: 134)meta.notecharJ/ApJ/596/944/table4Source catalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCXOSEXSIThe IAU-registered name (JHHMMSS.s+DDMMSS)meta.id;meta.maincharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainOAAOff axis anglearcmininstr.offsetfloatHctsBackground subtracted hard band (2.1-7keV) countsctphot.count;em.X-rayfloatHBkEstimated background counts within hard counts extraction aperturectinstr.backgroundfloatHSNRSignal-to-noise ratio of the hard detectionstat.snrfloatHFluxUnabsorbed hard band (2.0-10keV) flux in units of 10^-15^erg/cm^2^/saW.m**-2phot.flux;em.X-rayfloatSctsBackground subtracted soft band (0.3-2.1keV) countsctphot.count;em.X-raydoubleSBkEstimated background counts within soft counts extraction aperturectinstr.backgroundfloatS/NSignal-to-noise ratio of the soft detectionstat.snrfloatSFluxUnabsorbed soft band (0.5-2.0keV) flux in units of 10^-15^erg/cm^2^/saW.m**-2phot.flux;em.X-raydoubleHRRatioHardness ratio (1)phot.flux;arith.ratiofloatCFlag[0/1] Cluster flag (2)meta.codeintJ/ApJ/596/944/table6Soft-band only source catalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCXOSEXSIIAU-registered name (JHHMMSS.s+DDMMSS)meta.id;meta.maincharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainOAAOff axis anglearcmininstr.offsetfloatSctsBackground subtracted soft band (0.5-2.1keV) countsctphot.count;em.X-rayfloatSBkEstimated background counts within soft counts extraction aperturectinstr.backgroundfloatSSNRSignal-to-noise ratio of the soft detectionstat.snrfloatSFluxUnabsorbed soft (0.5-2.0keV) flux, in units of 10^-15^erg/cm^2^/saW.m**-2phot.flux;em.X-rayfloat