J/MNRAS/326/1161ivo://CDS.VizieR/J/MNRAS/326/1161doi:10.26093/cds/vizier.73261161CDSMorley J.E.Briggs K.R.Pye J.P.Favata F.Micela G.Sciortino S.2024-06-27T20:17:28Z2006-04-06T22:03:34ZCDS support team

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

cds-question@unistra.frsurveyslate-type-starsx-ray-sourcesphotometryWe have performed a moderately deep soft X-ray (0.1-2keV) survey of the Galactic plane using pointed observations with the ROSAT Position Sensitive Proportional Counter (PSPC). The survey is more than an order of magnitude more sensitive than previous X-ray surveys near the Galactic plane. The data consist of nine fields each of ~10ks exposure, pointed at positions on or very close to the Galactic plane (|b|<0.3{deg}) in the longitude range 180{deg}<~l<~280{deg}. This region has relatively low X-ray absorbing material out to distances of several hundred pc and presents fewer source-confusion problems than at other longitudes. The total sky area surveyed was 2.5deg^2^ this yielded 93 sources, 89 of which were detected in the hard (0.4-2.0keV) band. Nine sources were detected in both soft (0.1-0.4keV) and hard bands. In the hard band, the survey coverage is 90 per cent for sources brighter than 0.002count/s (~2x10^-14^erg/cm^2^/s), but falls steeply below this value, with the weakest sources being ~0.001count/s. The median limiting flux is <~0.0013count/s (~1.3x10^14^erg/cm^2^/s). There are 64 sources with hard-band count rates >0.002count/s. We present the catalogue of X-ray sources and the number-flux relations (logN-logS). Eighteen sources have possible identifications from the SIMBAD data base. We have searched the Tycho-2 (Cat. <I/259>) and USNO-A2.0 (Cat. <I/252>) catalogues to find all possible optical counterparts brighter than 19th magnitude, and attempt to classify these on the basis of log(FX/Fopt) versus optical colour diagrams and near-infrared photometry from the 2MASS Second Incremental Data Release (Cat. <B/2mass>). Hence, we have found the majority of these sources to be consistent with being late-type main-sequence stars, as previous studies have proposed from incompletely identified surveys. Comparison of the measured number-flux relations with predictions of Galactic (stellar) and extragalactic populations supports the view that the population of young stars in the plane is denser than previously thought.2001MNRAS.326.1161Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/326/1161CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIX/30 : Second ROSAT PSPC Catalog (ROSAT, 2000)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/326/1161https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/326/1161http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/326/1161https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/326/1161https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/326/1161http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/326/1161GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/326/1161/table23 (Sources detected in the hard band (0.4-2keV))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/326/1161/table23?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/326/1161/table23?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/326/1161/table23?GETtext/xml+votable180.050000true86.167791728.95980560.005555555555555556Cone search capability for table J/MNRAS/326/1161/table4 (Possible optical and near-infrared counterparts to X-ray sources detected in this survey)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/326/1161/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/326/1161/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/326/1161/table4?GETtext/xml+votable180.050000true86.165416728.95561110.0055555555555555565/5387 6/21515 21540 22036 22222-22223 22245 23947 23969 24466 24472 37343 38026 39416https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/326/1161?format=asciiX-rayOpticaldefaultJ/MNRAS/326/1161/table23Sources detected in the hard band (0.4-2keV)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[MBP2001]Source numbermeta.id;meta.mainintprimaryFieldField numbermeta.id;obs.fieldintRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainSigH? Significance of detection in Hard band in equivalent Gaussian {sigma}stat.fit.goodnessfloatnullablen_SigH[*] *=99% significance of detection in H bandmeta.notecharl_CRHLimit flag on CRmeta.code.errorcharCRHCount Rate in Hard (0.4-2keV) bandct/ksphot.count;em.X-rayfloate_CRH? rms uncertainty on CRHct/ksstat.errorfloatnullableNote[ST] Notes (1)meta.notecharSigS? Significance of detection in Soft band in equivalent Gaussian {sigma}stat.fit.goodnessfloatnullableCRS? Count Rate in Soft (0.1-0.4keV) bandct/ksphot.count;em.X-rayfloatnullablee_CRS? rms uncertainty on CRSct/ksstat.errorfloatnullablel_HRLimit flag on HRmeta.code.errorcharHR? Hardness ratio, HR=(H-S)/(H+S)phot.flux;arith.ratiofloatnullablee_HR? rms uncertainty on HRstat.errorfloatnullableJ/MNRAS/326/1161/table4Possible optical and near-infrared counterparts to X-ray sources detected in this surveySpTypeSpectral type (3)src.spTypecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[MBP2001]Numbermeta.id;meta.mainintm_[MBP2001]Letter running in alphabetical order with separation from X-ray source positionmeta.code.multipcharRAJ2000? Optical right ascension (J2000.0)pos.eq.ra;meta.mainnullableDEJ2000? Optical declination (J2000.0)pos.eq.dec;meta.mainnullableSep? Separation from X-ray source positionarcsecpos.angDistancefloatnullabler_RAh[UTS2] Source of position and optical photometry (1)meta.bibcharVRmag? Optical magnitude (V from Tycho2 or R from USNO-A2.0)magphot.mag;em.optfloatnullableB-VR? Optical colour (B-V from Tycho2 or B-R from USNO-A2.0)magphot.color;em.opt.B;em.opt.Rfloatnullablel_FX/FoptLimit flag on logFX/Foptmeta.code.error;phys.abundcharFX/Fopt? X-ray to optical flux ratio (logFX/FV from Tycho2 or logFX/FR from USNO-A2.0)phot.flux;arith.ratiofloatnullableCL[CENU] Classification from logFX/Fopt versus colour diagram (2)meta.code.classcharl_JmagLimit flag on Jmagmeta.code.error;phot.mag;em.IR.JcharJmag? J magnitudemagphot.mag;em.IR.Jfloatnullablel_J-HLimit flag on J-Hmeta.code.error;phot.color;em.IR.JcharJ-H? J-H colour indexmagphot.color;em.IR.J;em.IR.Hfloatnullablee_J-H? rms uncertainty on J-Hmagstat.error;phot.color;em.IR.Jfloatnullablel_H-KsLimit flag on H-Ksmeta.code.errorcharH-Ks? H-Ks colour indexmagphot.color;em.IR.H;em.IR.Kfloatnullablee_H-Ks? rms uncertainty on H-Ksmagstat.errorfloatnullableMS[YN?] Position on a near-IR two-colour diagram is consistent with an MS star flagmeta.codecharNotesNotes (luminosity units are erg/s=10^-7^W)meta.notechar