J/AJ/132/1100ivo://CDS.VizieR/J/AJ/132/1100doi:10.26093/cds/vizier.51321100CDSWolk S.J.Spitzbart B.D.Bourke T.L.Alves J.2017-06-12T08:24:57Z2010-01-19T14:58:18ZCDS support team

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

cds-question@unistra.frh-ii-regionsinfrared-sourcesx-ray-sourcesWe report on results of a 96.7ks Chandra observation of one of the youngest, most embedded, and most massive young stellar clusters studied in X-rays: RCW 38. We detect 460 sources in the field, of which 360 are confirmed to be associated with the RCW 38 cluster. The cluster members range in luminosity from 10^30^ to 10^33.5^ergs/s. Over 10% of the cluster members with over 100 counts exhibit flares, while about 15% of the cluster members with over 30 counts are variable. Of the sources identified as cluster members, 160 have near-infrared (NIR) counterparts either in the Two Micron All Sky Survey database or detected via Very Large Telescope observations. Of these, about 20% appear to have optically thick disks. An additional 353 members are identified through NIR observations, of which at least 50% possess optically thick disks. We fit over 100 X-ray sources as absorbed Raymond-Smith-type plasmas and find that the column to the cluster members varies from 10^21.5^ to 10^23^cm^-2^. We compare the gas to dust absorption signatures in these stars and find NH=A_V_(2x10^21^)cm^-2^. We find that the cluster contains 31 candidate OB stars and is centered about 10" (0.1pc) west of the primary source of the ionization, the O5 star IRS 2. The cluster has a peak central density of about 400 X-ray sources/pc^2^. We estimate that the total cluster membership exceeds 2000 stars.2006AJ....132.1100Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/132/1100CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/132/1100https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/132/1100http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/132/1100https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/132/1100https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/132/1100http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/132/1100GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/132/1100/table1 (X-ray sources detected in the RCW 38 field)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/132/1100/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/132/1100/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/132/1100/table1?GETtext/xml+votable180.050000true134.5885833-47.51866670.005555555555555556Cone search capability for table J/AJ/132/1100/table12 (IR Photometry in the VLT field (non-X-ray sources))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/132/1100/table12?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/132/1100/table12?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/132/1100/table12?GETtext/xml+votable180.050000true134.795925-47.497169440.005555555555555556Cone search capability for table J/AJ/132/1100/table13 (Candidate OB stars in RCW 38)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/132/1100/table13?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/132/1100/table13?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/132/1100/table13?GETtext/xml+votable180.050000true134.6827917-47.48252780.0055555555555555566/378727.952274030004205e-20 1.7798557115773645e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/132/1100?format=asciiX-rayInfrareddefaultJ/AJ/132/1100/table1X-ray sources detected in the RCW 38 fieldrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[WSB2006]Running source numbermeta.id;meta.mainintprimaryCXOJSource namemeta.idcharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainOffAxisOff-axis distancearcsecpos.angDistancefloatNctsNet counts (1)ctphot.count;em.X-rayfloatB95Number of intervals of constant flux at 95% significance (2)src.var.indexintB99Number of intervals of constant flux at 99% significance (2)src.var.indexintSimbadSimbad column added by the CDSmeta.ref.urlcharJ/AJ/132/1100/q25Quartile Values of probable members andQ25The 25% quartile valuestat.fit.paramfloate_Q25Error in Q25stat.errorfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMSimbad column added by the CDSmeta.code.memberchar[WSB2006]Running source numbermeta.id;meta.mainintmThe median quartile (=Q50)stat.fit.paramfloate_mError in mstat.errorfloatQ75The 75% quartile valuestat.fit.paramfloate_Q75Error in Q75stat.errorfloatlog(m/(1-m))Log of the m/(1-m) valuestat.fit.paramfloatRatioThe 3*Q25/Q75 ratiometa.notefloatJ/AJ/132/1100/fitX-ray spectral fitsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMSimbad column added by the CDSmeta.code.memberchar[WSB2006]Running source numbermeta.id;meta.mainintchi2/dofThe {chi}^2^ per d.o.f. (1)stat.fit.paramfloatNHModel hydrogen column density1e+22cm**-2phys.columnDensity;meta.modelledfloate_NH? Error in NH1e+22cm**-2stat.errorfloatnullablel_kTLimit flag on kTmeta.code.error;phys.energycharkTRaymond-Smith model temperaturekeVphys.temperaturefloatf_kTIndicates lower limit on the error in kTmeta.codechare_kT? Error in kTkeVstat.error;phys.energyfloatnullablelogFLog of the unabsorbed flux in units of ergs/cm^2^/slog(mW.m**-2)stat.fit.paramfloatlogL? Log of the luminosity in units of erg/s (2)log(1e-07W)phys.luminosityfloatnullableJ/AJ/132/1100/photIR photometry of X-ray sourcesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMSimbad column added by the CDSmeta.code.memberchar[WSB2006]Running source numbermeta.id;meta.mainintIRNameInfrared identificationmeta.idcharOffsetX-ray and IR position offsetpos.angDistancefloatJmag? The J band magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag? Error in Jmagmagstat.error;phot.mag;em.IR.JfloatnullableHmag? The H band magnitudemagphot.mag;em.IR.Hfloatnullablee_Hmag? Error in Hmagmagstat.error;phot.mag;em.IR.HfloatnullableKmag? The K band magnitudemagphot.mag;em.IR.Kfloatnullablee_Kmag? Error in Kmagmagstat.error;phot.mag;em.IR.KfloatnullableAV? The V band extinctionmagphys.absorption;em.opt.VfloatnullableModelType of emitting surface assumed (1)meta.id;stat.fitcharFlagsAdditional flags (2)meta.code.errorcharJ/AJ/132/1100/table12IR Photometry in the VLT field (non-X-ray sources)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIRNameInfrared identification (JHHMMSS.ss+DDMMSS.s)meta.idcharRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainJmagThe J band magnitudemagphot.mag;em.IR.Jfloate_JmagError in Jmagmagstat.error;phot.mag;em.IR.JfloatHmagThe H band magnitudemagphot.mag;em.IR.Hfloate_HmagError in Hmagmagstat.error;phot.mag;em.IR.HfloatKmagThe K band magnitudemagphot.mag;em.IR.Kfloate_KmagError in Kmagmagstat.error;phot.mag;em.IR.KfloatAVThe minimum V band extinctionmagphys.absorption;em.opt.V;stat.minfloatSimbadSimbad column added by the CDSmeta.refcharJ/AJ/132/1100/table13Candidate OB stars in RCW 38recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[WSB2006]? Running source numbermeta.id;meta.mainintnullableVLTVLT number for the two VLT-only sources (VLT NNN)meta.idcharRAJ2000Right ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Declination (J2000.0)pos.eq.dec;meta.mainOffAxisDistance from the cluster centerarcsecpos.angDistancefloatAV(IR)? V band extinction derived from the IR methodmagphys.absorptionfloatnullableAV(NH)? V band extinction derived from the X-ray methodmagphys.absorptionfloatnullableKsMAG? Absolute Ks magnitudemagphys.magAbs;em.IR.KfloatnullablelogLbolBolometric luminositylog(solLum)phys.luminosityfloatl_log(LX/Lbol)Limit flag on log(LX/Lbol)meta.code.errorcharlog(LX/Lbol)X-ray-to-bolometric luminosity ratiophys.luminosity;arith.ratiofloat