J/ApJS/184/84ivo://CDS.VizieR/J/ApJS/184/84doi:10.26093/cds/vizier.21840084CDSWright N.J.Drake J.J.2018-02-02T10:34:12Z2009-10-23T16:19:45ZCDS support team

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

cds-question@unistra.frstellar-associationsearly-type-starsx-ray-sourcesinfrared-photometryWe present a catalogue of 1696 X-ray sources detected in the massive star forming region (SFR) Cygnus OB2 and extracted from two archival Chandra observations of the center of the region. A deep source extraction routine, exploiting the low background rates of Chandra observations was employed to maximize the number of sources extracted. Observations at other wavelengths were used to identify low count-rate sources and remove likely spurious sources. Monte Carlo simulations were also used to assess the authenticity of these sources. X-ray spectra were fitted with thermal plasma models to characterize the objects and X-ray light curves were analyzed to determine their variability. We used a Bayesian technique to identify optical or near-IR counterparts for 1501 (89%) of our sources, using deep observations from the INT Photometric H-alpha Survey, the Two Micron All Sky Survey, and the UKIRT Infrared Deep Sky Survey-Galactic plane Survey. 755 (45%) of these objects have six-band r', H-alpha, i', J, H, and K optical and near-IR photometry. From an analysis of the Poisson false-source probabilities for each source we estimate that our X-ray catalogue includes <1% of false sources, and an even lower fraction when only sources with optical or near-IR associations are considered. A Monte Carlo simulation of the Bayesian matching scheme allows this method to be compared to more simplified matching techniques and enables the various sources of error to be quantified. The catalogue of 1696 objects presented here includes X-ray broad band fluxes, model fits, and optical and near-IR photometry in what is one of the largest X-ray catalogue of a single SFR to date. The high number of stellar X-ray sources detected from relatively shallow observations confirms the status and importance of Cygnus OB2 as one of our Galaxy's most massive SFRs.2009ApJS..184...84Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/184/84CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/101/1408 : Massive stars in Cyg OB2 (Massey+ 1991)J/ApJ/664/102 : Radial velocity survey of Cyg OB2 association (Kiminki+, 2007)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/184/84https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/184/84http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/184/84https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/184/84https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/184/84http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/184/84GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/184/84/catalog (X-ray sources detected in Cyg OB2 region:)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/184/84/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/184/84/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/184/84/catalog?GETtext/xml+votable180.050000true307.817166741.44222220.0055555555555555566/14692 14693https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/184/84?format=asciiX-rayInfrareddefaultJ/ApJS/184/84/catalogX-ray sources detected in Cyg OB2 region:MfitModel fit type (1)meta.id;stat.fitcharJmag? J band magnitudemagphot.mag;em.IR.JfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqRunning identification numbermeta.id;meta.mainintprimaryRAJ2000Hour of Right Ascension (J2000) (1)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000) (1)pos.eq.dec;meta.mainthetaOff-axis anglearcmininstr.offsetfloatAreaSource extraction region areapixstat.fit.paramintfPSFPoint Spread Function fraction in extraction regioninstr.det.psf;obs.field;arith.ratiofloatSigSource detection significancestat.likelihood;obsfloatlgPcoPoisson probability log of a coincidence (2)stat.probabilityfloatExpFull exposure time (3)kstime.duration;obs.exposurefloatEx0.5-8keV median energy (4)keVem.energyfloatlgPksLog Kolmogorov-Smirnov probability (5)stat.probabilityfloatCntsNet 0.5-8keV band countsctphot.count;em.X-raydoubleE_CntsUpper 1{sigma} error on Cntsctstat.error;stat.maxfloate_CntsLower 1{sigma} error on Cntsctstat.errorfloatFullNet 0.5-8keV band count ratect/ksphot.count;em.X-rayfloatSoftNet 0.2-2keV band count ratect/ksphot.count;em.X-rayfloatHardNet 2-8keV band count ratect/ksphot.count;em.X-rayfloatFld[1/3] Source field number (6)meta.id;obs.fieldintFlg[EN] Warning detection flag (7)meta.codecharl_logNHLimit flag on logNHmeta.code.errorcharlogNH? log of Hydrogen column density (2)log(cm**-2)phys.columnDensityfloatnullableE_logNH? Upper 90% confidence interval in logNH (3)log(cm**-2)stat.error;stat.maxfloatnullablee_logNH? Lower 90% confidence interval in logNH (3)log(cm**-2)stat.errorfloatnullablel_kTLimit flag on kTmeta.code.error;phys.energycharkT? Model fit thermal plasma temperaturekeVphys.energy;meta.modelledfloatnullableE_kT? Upper 90% confidence interval in kT (3)keVstat.error;stat.maxfloatnullablee_kT? Lower 90% confidence interval in kT (3)keVstat.error;phys.energyfloatnullablelogLlog 0.5-8keV band luminosity (4)log(1e-07W)phys.luminosity;em.X-rayfloatE_logL? Upper 90% confidence interval in logL (3)log(1e-07W)stat.error;stat.maxfloatnullablee_logL? Lower 90% confidence interval in logL (3)log(1e-07W)stat.errorfloatnullablelogLs? Log 0.5-2keV band luminosity (4)log(1e-07W)phys.luminosity;em.X-rayfloatnullablelogLh? Log 2-8keV band luminosity (4)log(1e-07W)phys.luminosity;em.X-rayfloatnullableOff? X-ray and optical/NIR position offsetarcsecpos;arith.difffloatnullabler'mag? IPHAS r' band magnitudemagphot.mag;em.opt.Rfloatnullablee_r'mag? Error in r'magmagstat.error;phot.mag;em.opt.Rfloatnullablei'mag? IPHAS i' band magnitudemagphot.mag;em.opt.Ifloatnullablee_i'mag? Error in i'magmagstat.error;phot.mag;em.opt.IfloatnullableHamag? IPHAS H{alpha} band magnitudemagphot.flux;em.line.Halphafloatnullablee_Hamag? Error in Hamagmagstat.error;phot.mag;em.IR.Hfloatnullablee_Jmag? Error in Jmagmagstat.error;phot.mag;em.IR.JfloatnullableHmag? J band magnitudemagphot.mag;em.IR.Hfloatnullablee_Hmag? Error in Hmagmagstat.error;phot.mag;em.IR.HfloatnullableKsmag? Ks band magnitudemagphot.mag;em.IR.Kfloatnullablee_Ksmag? Error in Kmagmagstat.error;phot.mag;em.IR.KfloatnullableNIRNear-IR photometry source (2)meta.ref;pos.framechar2Mq2MASS IJKs photometry quality flagsmeta.code.qualchar2MDisplay the 2MASS data (Cutri et al. 2003, Cat. II/246)meta.ref.urlchar[AFM2007]? Number in Albacete Colombo et al. 2007 (Cat. J/A+A/464/211)meta.idintnullableSpTLiterature MK spectral typesrc.spTypecharr_SpTReference for Sptype (3)meta.ref;pos.framecharONameOther name (4)meta.idchar