J/A+A/553/A12ivo://CDS.VizieR/J/A+A/553/A12doi:10.26093/cds/vizier.35530012CDSNebot Gomez-Moran A.Motch C.Barcons X.Carrera F.J.Ceballos M.T.,Cropper M.Grosso N.Guillout P.Herent O.Mateos S.Michel L.,Osborne J.P.Pakull M.Pineau F.-X.Pye J.P.Roberts T.P.Rosen S.R.,Schwope A.D.Watson M.G.Webb N.2017-06-30T05:47:52Z2013-09-28T11:26:13ZCDS support team

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

cds-question@unistra.frastronomical-object-identificationphotometryMany different classes of X-ray sources contribute to the Galactic landscape at high energies. Although the nature of the most luminous X-ray emitters is now fairly well understood, the population of low-to-medium X-ray luminosity (LX=10^27-34^erg/s) sources remains much less studied, our knowledge being mostly based on the observation of local members. The advent of wide field and high sensitivity X-ray telescopes such as XMM-Newton now offers the opportunity to observe this low-to-medium LX population at large distances. We report on the results of a Galactic plane survey conducted by the XMM-Newton Survey Science Centre (SSC). Beyond its astrophysical goals, this survey aims at gathering a representative sample of identified X-ray sources at low latitude that can be used later on to statistically identify the rest of the serendipitous sources discovered in the Milky Way. The survey is based on 26 XMM-Newton observations, obtained at |b|<20{deg}, distributed over a large range in Galactic longitudes and covering a summed area of 4deg^2^. The flux limit of our survey is 2x10^-15^erg/cm^2^/s in the soft (0.5-2keV) band and 1x10^-14^erg/cm^2^/s in the hard (2-12keV) band. We detect a total of 1319 individual X-ray sources. Using optical follow-up observations supplemented by cross-correlation with a large range of multi-wavelength archival catalogues we identify 316 X-ray sources. This constitutes the largest group of spectroscopically identified low latitude X-ray sources at this flux level. The majority of the identified X-ray sources are active coronae with spectral types in the range A-M at maximum distances of ~1kpc. The number of identified active stars increases towards late spectral types, reaching a maximum at K. Using infrared colours we classify 18% of the stars as giants. The observed distributions of FX/FV, X-ray and infrared colours indicates that our sample is dominated by a young (100Myr) to intermediate (600Myr) age population with a small contribution of close main sequence or evolved binaries. We find other interesting objects such as cataclysmic variables (d~0.6-2kpc), low luminosity high mass stars (likely belonging to the class of {gamma}-Cas-like systems, d~1.5-7kpc), T Tauri and Herbig-Ae stars. A handful of extragalactic sources located in the highest Galactic latitude fields could be optically identified. For the 20 fields observed with the EPIC pn camera, we have constructed logN(>S)-logS curves in the soft and hard bands. In the soft band, the majority of the sources are positively identified with active coronae and the fraction of stars increases by about one order of magnitude from b=60{deg} to b=0{deg} at an X-ray flux of 2x10^-14^erg/cm^2^/s. The hard band is dominated by extragalactic sources, but there is a small contribution from a hard Galactic population formed by CVs, HMXB candidates or {gamma}-Cas-like systems and by some active coronae that are also detected in the soft band. At b=0{deg} the surface density of hard sources brighter than 1x10^-13^erg/cm^2^/s steeply increases by one order of magnitude from l=20{deg} to the Galactic centre region (l=0.9{deg}).2013A&A...553A..12Nhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/553/A12CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/284 : The USNO-B1.0 Catalog (Monet+ 2003)I/305 : The Guide Star Catalog, Version 2.3.2 (GSC2.3) (STScI, 2006)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/553/A12https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/553/A12http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/553/A12https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/553/A12https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/553/A12http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/553/A12GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/553/A12/table1 (Target fields and source classification)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/553/A12/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/553/A12/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/553/A12/table1?GETtext/xml+votable180.050000true282.93610.14960.005555555555555556Cone search capability for table J/A+A/553/A12/Xsources (X-ray sources detected in the 26 different fields observed in this study, with their X-ray parameters and optical and infrared counterparts)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/553/A12/Xsources?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/553/A12/Xsources?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/553/A12/Xsources?GETtext/xml+votable180.050000true337.5437539.3008330.0055555555555555566/2941 2943 3029 3055 3310 12796 12798 12804 13189 13191 13558 13564 13797 13799 13808 13945 13947 14018 14303 14316 14318 23828 23830 23952 24329 24331 28830-28831 29097 29511 29522-29523 30313 30315 30400 30402 37845 38442 38528 40613 40615 40834-40835 42417 424198.650015785639275e-20 9.710690472292815e-20https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/553/A12?format=asciiX-rayOpticaldefaultJ/A+A/553/A12/table1Target fields and source classificationFieldField designationmeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintn_Seq[bf] Sample: b = Optically bright sample (Rlim~17), f = Optically faint sample (Rlim~21)meta.notecharSeqSequential field numberobs.fieldintprimaryGLONGalactic longitudedegpos.galactic.lonGLATGalactic latitudedegpos.galactic.latNHCalculated hydrogen column density (1)cm**-2phys.columnDensity;meta.modelleddoubleObsIDXMM Observation IDmeta.id;obscharTexpEPIC-pn exposure timekstime.duration;obs.exposureintn_Texp[M] M if EPIC-MOS exposure timemeta.notecharNtotTotal number of 2XMMi-DR3 sources detected (2)meta.numberintACNumber of identified active coronae (2)meta.numberintAC%Percentage of identified active coronae (2)%meta.numberintHMBXNumber of identified High-mass X-ray binaries (2)meta.numberintpMSNumber of identified pre-main sequence stars (2)meta.numberintEGNumber of identified extragalactic sources (2)meta.numberintunNumber of unidentified sources (2)meta.numberint_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)degpos.eq.decnullableindexedJ/A+A/553/A12/XsourcesX-ray sources detected in the 26 different fields observed in this study, with their X-ray parameters and optical and infrared counterpartsKsmag? 2MASS Ks magnitudemagphot.mag;em.IR.KfloatnullableGSCGSC association name (AANNNNNNNN)meta.id.crosscharSeqField number, as in table 1obs.fieldintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint2XMM2XMM name of XMM-DR3 source (JHHMMSS.s+DDMMSS)meta.ref;pos.framecharr9090% confidence error radiusarcsecstat.error;phys.angSizefloatCRpn1? Count rate in energy band 1 [0.5-2.0keV]ct/ksphot.count;em.X-rayfloatnullablee_CRpn1? rms uncertainty on CRpnB1ct/ksstat.errorfloatnullableCRpn2? Count rate in energy band 2 [2.0-12.0keV]ct/ksphot.count;em.X-rayfloatnullablee_CRpn2? rms uncertainty on CRpnB2ct/ksstat.errorfloatnullable2MASS2MASS association name (HHMMSSss+DDMMSSs)meta.id.crosschardx2? Distance between X-ray and 2MASS sourcearcsecpos;arith.difffloatnullablePid2? Probability of 2MASS identificationstat.fit.goodnessfloatnullabledxg? Distance between X-ray and GSC sourcearcsecpos;arith.difffloatnullablePidg? Probability of GSC identificationstat.fit.goodnessfloatnullableVmag? GSC V magnitudemagphot.mag;em.opt.VfloatnullableUSNOUSNO-B1.0 association name (NNNN-NNNNNNN)meta.id.crosschardxu? Distance between X-ray and USNO sourcearcsecpos;arith.difffloatnullablePidu? Probability of USNO identificationstat.fit.goodnessfloatnullableRmag? USNO-B1.0 R2 magnitudemagphot.mag;em.opt.RfloatnullableClassClassification of the source (1)src.classcharSpTypeSpectral type (1)src.spTypecharn_SpType[sp image] Note (2)meta.notecharSimbadSimbad column added by the CDSmeta.ref.urlchar_RAX-ray position from 2XMM name (right ascension part)degpos.eq.ra;meta.main_DEX-ray position from 2XMM name (declination part)degpos.eq.dec;meta.main