J/ApJS/168/100ivo://CDS.VizieR/J/ApJS/168/100doi:10.26093/cds/vizier.21680100CDSWang J.Townsley L.K.Feigelson E.D.Getman K.V.Broos P.S.,Garmire G.P.Tsujimoto M.2017-09-27T05:55:43Z2009-09-26T11:27:28ZCDS support team

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

cds-question@unistra.fropen-star-clusterspre-main-sequence-starsx-ray-sourcesphotometryinfrared-sourcesWe present the first high spatial resolution X-ray study of the massive star-forming region NGC 6357, obtained in a 38ks Chandra/ACIS observation. Inside the brightest constituent of this large HII region complex is the massive open cluster Pismis 24. It contains two of the brightest and bluest stars known, yet remains poorly studied; only a handful of optically bright stellar members have been identified. We investigate the cluster extent and initial mass function and detect ~800 X-ray sources with a limiting sensitivity of ~10^30^ergs/s; this provides the first reliable probe of the rich intermediate-mass and low-mass population of this massive cluster, increasing the number of known members from optical study by a factor of ~50.2007ApJS..168..100Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/168/100CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/mk : Catalogue of Stellar Spectral Classifications (Skiff, 2007)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)J/ApJ/574/258 : X-ray-emitting young stars in the Orion nebulaJ/ApJ/575/354 : Young stellar objects in the NGC 1333 (Getman+, 2002)J/ApJ/614/267 : Chandra sources in Cha I North (Feigelson+, 2004)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/168/100https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/168/100http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/168/100https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/168/100https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/168/100http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/168/100GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/168/100/Xsources (Basic and tentative sources (tables 1 and 2 of the paper))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/168/100/Xsources?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/168/100/Xsources?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/168/100/Xsources?GETtext/xml+votable180.050000true260.97493194-34.147448060.005555555555555556Cone search capability for table J/ApJS/168/100/table5 (Stellar counterparts and classifications)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/168/100/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/168/100/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/168/100/table5?GETtext/xml+votable180.050000trueCone search capability for table J/ApJS/168/100/table6 (Known O and early-B stars in Pismis 24)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/168/100/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/168/100/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/168/100/table6?GETtext/xml+votable180.050000true261.1812083-34.19916670.0055555555555555566/424628.650015785639275e-20 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/168/100?format=asciiOpticalInfraredX-raydefaultJ/ApJS/168/100/XsourcesBasic and tentative sources (tables 1 and 2 of the paper)SigPhotometric significancestat.fit.goodnessfloatESource median energy (5)keVem.energyfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintn_[WTF2007]Simbad column added by the CDSmeta.codechar[WTF2007]Source sequence numbermeta.id;meta.mainintprimaryCXOUJChandra source identification (HHMMSS.ss+DDMMSS.s)meta.idcharRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.maine_posPositional errorarcsecstat.errorfloatthetaOff-axis anglearcmininstr.offsetfloatFctsNet full (0.5-8keV) extracted countsctphot.count;em.X-rayfloate_FctsThe 1{sigma}-equivalent uncertainty in Fcts, based on Poisson statisticsctstat.errorfloatBkgNet full background extracted countsctinstr.background;src.netfloatHctsNet hard (2-8keV) extracted countsctphot.count;em.X-rayfloatPSFFraction of PSF used for source extraction (1)instr.det.psffloatl_logPB[<] Limit flag on logPBmeta.code.errorcharlogPBLog of the probability that the extracted full band counts are solely from backgroundstat.probabilityfloatAnom[geps] Source Anomaly (2)meta.codecharVar[abc] Source variability (3)meta.codecharExpEffective exposure time (4)kstime.duration;obs.exposurefloatJ/ApJS/168/100/table5Stellar counterparts and classificationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[WTF2007]Source sequence numbermeta.id;meta.mainintCXOUJChandra source identification (HHMMSS.ss+DDMMSS.s)meta.idchar2M[NY] A 2MASS counterpart? (No, Yes or blank) (1)meta.codecharSIR[NY] A SIRIUS (near-IR camera on 1.4m IRSF tel.) counterpart? (No, Yes or blank) (1)meta.codecharHST[NY] A HST counterpart? (No, Yes or blank) (1)meta.codecharFlagX-ray source flag; see section 5.5 for detailsmeta.code.errorcharRAJ2000? 2MASS Hour of Right Ascension (J2000)pos.eq.ra;meta.mainnullableDEJ2000? Degree of Declination (J2000)pos.eq.dec;meta.mainnullableOffset? 2MASS/X-ray offsetarcsecpos;arith.difffloatnullableJ-H? 2MASS (J-H) color indexmagphot.color;em.IR.J;em.IR.HfloatnullableH-K? 2MASS (H-K_s_) color indexmagphot.color;em.IR.H;em.IR.KfloatnullableKmag? 2MASS K_s_ band magnitudemagphot.mag;em.IR.Kfloatnullableq2M2MASS photometry quality flags (2)meta.code.qual;photcharc2M2MASS confusion and contamination flags (3)meta.codecharJ/ApJS/168/100/table6Known O and early-B stars in Pismis 24SeqSequence (7)meta.notecharNameSource name (1)meta.id;meta.maincharf_SpType[i] Tentative spectral type (2)meta.codecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSpTypeMK spectral type (3)src.spTypecharRAJ2000Hour of Right Ascension (J2000.0) (4)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000.0) (4)pos.eq.dec;meta.mainVmagV magnitude (3)magphot.mag;em.opt.VfloatU-B? U-B color index (3)magphot.color;em.opt.U;em.opt.Bfloatnullableu_U-B[::] Uncertainty flag on U-Bmeta.code.error;phot.color;em.opt.UcharB-VB-V color index (3)magphot.color;em.opt.B;em.opt.VfloatV-JV-J color index (5)magphot.color;em.opt.V;em.IR.JfloatJ-HJ-H color index (5)magphot.color;em.IR.J;em.IR.HfloatH-KsH-K_s_ color index (5)magphot.color;em.IR.H;em.IR.KfloatKsmag2MASS Ks magnitude (5)magphot.mag;em.IR.KfloatAVExtinction (6)magphys.absorptionfloatlogLX? Log of absorption-corrected full-band luminosity L_t,c_ (8)log(1e-07W)phys.luminosity;em.X-rayfloatnullablelogN? Log of X-ray-derived column densitylog(cm**-2)phys.columnDensityfloatnullablel_logLbol[>] Upper limit flag on logLbolmeta.code.errorcharlogLbol? Log of the bolometric luminosity (8)log(1e-07W)phys.luminosityfloatnullableNotesNotes (9)meta.notecharSimbadNameSimbad column added by the CDSmeta.idcharXX-ray data of this starmeta.ref.urlcharJ/ApJS/168/100/table8X-ray selected candidate intermediate-mass starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[WTF2007]Source sequence numbermeta.id;meta.mainintCXOUJChandra source identification (HHMMSS.ss+DDMMSS.s)meta.idcharJmag2MASS J band magnitudemagphot.mag;em.IR.JfloatHmag2MASS H band magnitudemagphot.mag;em.IR.HfloatKsmag2MASS K_s_ band magnitudemagphot.mag;em.IR.KfloatAVThe V band extinction (1)magphys.absorption;em.opt.VfloatMassEstimated mass (1)solMassphys.massintDelK[s] Indicates significant K_s_ band excess (2)magphot.color.excesscharJ/ApJS/168/100/XspecX-ray spectroscopy (tables 3 and 4 of the paper)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintn_[WTF2007]Simbad column added by the CDSmeta.codechar[WTF2007]Source sequence numbermeta.id;meta.mainintCXOUJChandra source identification (HHMMSS.ss+DDMMSS.s)meta.idchare_logN? Lower limit uncertainty on logN (1)log(cm**-2)stat.errorfloatnullablel_logN[<] Limit flag on logNmeta.code.errorcharlogNLog of estimated hydrogen column density (2)log(cm**-2)phys.columnDensityfloatE_logN? Upper limit uncertainty on logN (1)log(cm**-2)stat.error;stat.maxfloatnullablee_kT? Lower limit uncertainty on kT (1)keVstat.error;phys.energyfloatnullablel_kT[>] Limit flag on kTmeta.code.error;phys.energycharkTPlasma energy (2)keVphys.temperaturefloatE_kT? Upper limit uncertainty on kT (1)keVstat.error;stat.maxfloatnullablee_logEM? Lower limit uncertainty on logEM (1)log(cm**-3)stat.errorfloatnullablelogEMLog of the plasma emission measure (2)log(cm**-3)phys.emissMeasurefloatE_logEM? Upper limit uncertainty on logEM (1)log(cm**-3)stat.error;stat.maxfloatnullablelogLsLog of the soft (0.5-2keV) band luminosity (3)log(1e-07W)phys.luminosity;em.X-rayfloatlogLhLog of the hard (2-8keV) band luminosity (3)log(1e-07W)phys.luminosity;em.X-rayfloatlogLhcLog of the absorption-corrected hard band luminosity (3)log(1e-07W)phys.luminosity;em.X-rayfloatlogLtLog of the total (0.5-8keV) luminosity (3)log(1e-07W)phys.luminosity;em.X-rayfloatlogLtcLog of the total absorption-corrected luminosity (3)log(1e-07W)phys.luminosity;em.X-rayfloatGood? Goodness of fit {chi}^2^_{nu}_stat.fit.goodnessfloatnullableNoteAdditional notes (4)meta.notechar