J/MNRAS/343/293ivo://CDS.VizieR/J/MNRAS/343/293doi:10.26093/cds/vizier.73430293CDSManners J.C.Johnson O.Almaini O.Willott C.J.Gonzalez-Solares E.,Lawrence A.Mann R.G.Perez-Fournon I.Dunlop J.S.Mcmahon R.G.,Oliver S.J.Rowan-Robinson M.Serjeant S.2024-06-28T20:17:28Z2007-02-14T21:03:48ZCDS support team

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

cds-question@unistra.frsurveysx-ray-sourcesWe present an analysis of two deep (75ks) Chandra observations of the European Large Area Infrared Space Observatory (ISO) Survey (ELAIS) fields N1 and N2 as the first results from the ELAIS deep X-ray survey. This survey is being conducted in well-studied regions with extensive multiwavelength coverage. Here we present the Chandra source catalogues along with an analysis of source counts, hardness ratios and optical classifications. A total of 233 X-ray point sources are detected in addition to two soft extended sources, which are found to be associated with galaxy clusters. An overdensity of sources is found in N1 with 30 per cent more sources than N2, which we attribute to large-scale structure. A similar variance is seen between other deep Chandra surveys. The source count statistics reveal an increasing fraction of hard sources at fainter fluxes. The number of galaxy-like counterparts also increases dramatically towards fainter fluxes, consistent with the emergence of a large population of obscured sources.2003MNRAS.343..293Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/343/293CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 2002)J/AJ/122/2810 : Chandra Deep Field North Survey. V. (Brandt+, 2001)J/ApJS/139/369 : Chandra Deep Field South. 1 Ms catalog (Giacconi+, 2002)J/AJ/126/632 : UBVRIz'HK' photometry of 2Ms CDFN X-ray sourcesJ/A+A/329/482 : The ROSAT Deep Survey. I. (Hasinger+, 1998)J/A+A/379/798 : ELAIS H{alpha} emitting galaxies (Pascual+, 2001)J/MNRAS/302/222 : ISO ELAIS 20cm VLA survey regions (Ciliegi+, 1999)J/MNRAS/305/297 : ISO ELAIS 1.4GHz survey (Gruppioni+, 1999)J/MNRAS/325/1173 : ISO ELAIS 15{mu}m survey (Lari+, 2001)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/343/293https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/343/293http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/343/293https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/343/293https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/343/293http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/343/293GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/343/293/elais (All ELAIS sources in fields N1 and N2)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/343/293/elais?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/343/293/elais?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/343/293/elais?GETtext/xml+votable180.050000true242.841166754.56741670.005555555555555556Cone search capability for table J/MNRAS/343/293/list (Sources detected in the 0.5-8keV, 0.5-2keV and 2-8keV band images)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/343/293/list?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/343/293/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/343/293/list?GETtext/xml+votable180.050000true242.68812305654.603590.005555555555555556Chandra6/9640 10153 10155https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/343/293?format=asciiX-raydefaultJ/MNRAS/343/293/elaisAll ELAIS sources in fields N1 and N2recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDIdentification number (N1_NNN or N2_NNN)meta.id;meta.maincharCXOENCXOEN1 (table 1) or CXOEN2 (table2) designation, JHHMMSS.s+DDMMSSmeta.idcharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.maine_PosError in positionarcsecstat.errorfloatNCountNet countsctphot.count;em.X-rayfloatS/NSignal-to-noise ratiostat.snrfloatl_F0.5-8keVLimit flag on F0.5-2keVmeta.code.errorcharF0.5-8keVFlux at (0.5-8keV) (in 10-17erg/cm2/s)1e-17W.m**-2phot.flux;em.X-rayfloate_F0.5-8keV? rms uncertainty on F0.5-8keV1e-17W.m**-2stat.errorfloatnullablel_F0.5-2keVLimit flag on F0.5-2keVmeta.code.errorcharF0.5-2keV? Flux at (0.5-2keV) (in 10-17erg/cm2/s)1e-17W.m**-2phot.flux;em.X-rayfloatnullablee_F0.5-2keV? rms uncertainty on F0.5-2keV1e-17W.m**-2stat.errorfloatnullablel_F2-8keVLimit flag on F2-8keVmeta.code.errorcharF2-8keV? Flux at (2-8keV) (in 10-17erg/cm2/s)1e-17W.m**-2phot.flux;em.X-rayfloatnullablee_F2-8keV? rms uncertainty on F2-8keV1e-17W.m**-2stat.errorfloatnullableHRHardness ratiophot.flux;arith.ratiofloate_HRrms uncertainty on HRstat.errorfloatJ/MNRAS/343/293/listSources detected in the 0.5-8keV, 0.5-2keV and 2-8keV band imagesMajAxisApproximate 3 sigma size of source major axisarcsecphys.angSizefloatMinAxisApproximate 3 sigma size of source minor axisarcsecphys.angSize;srcfloatPARotation angle of estimated source ellipsedegpos.posAng;pos.errorEllipsefloatCompComponent numbermeta.idintFluxBackground subtracted source flux in erg/cm^2^/s, calculated for the relevant band assuming a photon index of =1.7, (2)mW.m**-2phot.flux;em.X-raydoublee_FluxError on FluxmW.m**-2stat.error;phot.fluxdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDIdentification number (N1_NNN or N2_NNN)meta.id;meta.maincharDetDetection interval (0.5-2, 0.5-8 or 2-8keV)keVinstr.bandpasscharRAJ2000Right ascension (J2000) (1)pos.eq.ra;meta.mainDEJ2000Declination (J2000)(1)pos.eq.dec;meta.mainRankRank, in order of decreasing S/Nmeta.idinte_RAsError on right ascension of X-ray centroid (does not include astrometric error)degstat.error;pos.eq.radoublee_DEsError on declination of X-ray centroid (does not include astrometric error)degstat.error;pos.eq.decdoubleXposX-ray centroid position of unbinned Chandra imagepixpos.cartesian.xdoubleYposX-ray centroid position of unbinned Chandra imagepixpos.cartesian.y;instr.detdoublee_XposError on centroid positionpixstat.error;pos.cartesian.xfloate_YposError on centroid positionpixstat.error;pos.cartesian.yfloatNpix2Number of 0.984" (i.e. 2x2 binned image) pixels in WAVDETECT 'source cell'phys.area;instrintNctBackground subtracted source counts within the 'source cell'ctphot.count;em.X-rayfloate_NctError on source countsctstat.errorfloatBKGctBackground counts within the 'source cell'ctinstr.backgroundfloate_BKGctError on background countsctstat.errorfloatCRateSource count rate in 'source cell'count.cm**-2.s**-1phot.count;em.X-raydoublee_CRateError on source count ratecount.cm**-2.s**-1stat.errordoubleBKGrateBackground count rate in 'source cell'count.cm**-2.s**-1instr.backgrounddoublee_BKGrateError on background count ratecount.cm**-2.s**-1stat.error;phot.countdoubleEffAreaEffective area of detector at source positioncm**2phys.area;instrfloate_EffAreaError on effective areacm**2stat.errorfloatS/NSignal-to-noise as defined in paper I (2)stat.snrfloatPSFSizeEstimated size of detector PSF at source location: radius (in arcseconds) of the circle which encompasses 39.3% of the total counts of an unresolved sourcearcsecinstr.det.psffloatPSFRatioApproximate ratio of source size to detector PSF sizephys.angSize;srcfloat