J/A+A/464/211ivo://CDS.VizieR/J/A+A/464/211doi:10.26093/cds/vizier.34640211CDSAlbacete Colombo J.F.Flaccomio E.Micela G.Sciortino S.Damiani F.2017-06-29T08:56:25Z2008-01-28T10:31:33ZCDS support team

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

cds-question@unistra.frstellar-associationspre-main-sequence-starsx-ray-sourcesinfrared-photometryThe aim of this work is to identify the so far unknown low mass stellar population of the ~2Myr old Cygnus OB2 star forming region, and to investigate the X-ray and near-IR stellar properties of its members. We analyzed a 97.7ks Chandra ACIS-I observation pointed at the core of the Cygnus OB2 region. Sources were detected using the PWDETECT code and were positionally correlated with optical and near- IR catalogs from the literature. Source events were extracted with the Acis E XTRACT package. X-ray variability was characterized through the Kolmogorov-Smirnov test and spectra were fitted using absorbed thermal plasma models. We detected 1003 X-ray sources. Of these, 775 have near-IR counterparts and are expected to be almost all associated with Cygnus OB2 members.2007A&A...464..211Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/464/211CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/107/1433 : Cygnus OB2 polarimetry (Kobulnicky+, 1994)J/ApJS/149/123 : WSRT survey of Cygnus OB2 (Setia Gunawan+, 2003)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/464/211https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/464/211http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/464/211https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/464/211https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/464/211http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/464/211GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/464/211/catalog (Cygnus OB2 source catalog: X-ray sources and near-IR counterparts)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/464/211/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/464/211/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/464/211/catalog?GETtext/xml+votable180.050000true308.104541741.17211110.0055555555555555566/14692-146938.650015785639275e-20 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/464/211?format=asciiX-rayInfrareddefaultJ/A+A/464/211/catalogCygnus OB2 source catalog: X-ray sources and near-IR counterpartsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintn_[AFM2007]Simbad column added by the CDSmeta.ref.urlchar[AFM2007]Sequential numbermeta.recordintprimaryCXOCYGName (HHMMSS.ss+DDMMSS.s) CXOCYG JHHMMSS.ss+DDMMSS.s in Simbadmeta.idcharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainePosrms uncertainty on positionarcsecstat.errorfloatThetaOff-axis anglearcmininstr.offsetfloatSigniSignificance of detectionstat.likelihood;obsfloatAreaSource extraction areapixphys.areaintfPSF[0/1] PSF fraction of source events within the extraction area, assuming E=1.49keVinstr.saturationfloatCountsBackground-corrected extracted source counts in the 0.5-8.0keV band (in ct/photon)ctphot.count;em.X-rayintExpTimeExposure timekstime.duration;obs.exposurefloatCRtotTotal (0.5-8.0keV) band count rate (1)ct/ksphot.count;em.X-rayfloatCRsoftSoft (0.5-1.7keV) band count rate (1)ct/ksphot.count;em.X-rayfloatCRmedMedium (1.7-2.8keV) band count rate (1)ct/ksphot.count;em.X-rayfloatCRhardHard (2.8-8.0keV) band count rate (1)ct/ksphot.count;em.X-rayfloatExMedian photon energykeVem.energyfloatVarLogarithm of the KS-test significance, log(P_KS_) (2)stat.probability;src.varfloatn_Var[+] +: flare-like sourcesmeta.notecharCXOACCXOACJ name (HHMMSS.ss+DDMMSS.s)meta.idchar2MASS2MASSJ name (HHMMSSss+DDMMSSs)meta.idcharOff? Offsetarcsecpos.angDistancefloatnullableJmag? 2MASS J magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag? rms uncertainty on Jmagmagstat.error;phot.mag;em.IR.JfloatnullableHmag? 2MASS H magnitudemagphot.mag;em.IR.Hfloatnullablee_Hmag? rms uncertainty on Hmagmagstat.error;phot.mag;em.IR.HfloatnullableKsmag? 2MASS Ks magnitudemagphot.mag;em.IR.Kfloatnullablee_Ksmag? rms uncertainty on Ksmagmagstat.error;phot.mag;em.IR.Kfloatnullableq_JmagJ band photometric quality flag (1)meta.code.qualcharq_HmagH band photometric quality flag (1)meta.code.qualcharq_KsmagKs band photometric quality flag (1)meta.code.qualcharAV? Absorption in V bandmagphot.mag;em.opt.Vfloatnullablen_AV[n] n indicates stars with unconstrained AVmeta.notecharJ/A+A/464/211/table3X-ray source spectroscopyrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[AFM2007]Sequential numbermeta.recordintCountsCounts Background subtracted counts in the spectraphot.count;em.X-rayintlog(NH)Best fit hydrogen column densitycm**-2phys.columnDensity;meta.modelledfloate_log(NH)rms uncertainty on log(NH)cm**-2stat.errorfloatkT? Plasma temperaturekeVphys.temperaturefloatnullablee_kT? rms uncertainty on kTkeVstat.error;phys.energyfloatnullablelog(EM)Emission measurecm**-3phys.emissMeasurefloatchi2reduced chi^2^ value for the spectral fitstat.fit.chi2floatdofDegree of freedom for the spectral fitstat.fit.dofint