J/ApJ/753/117ivo://CDS.VizieR/J/ApJ/753/117doi:10.26093/cds/vizier.17530117CDSGuarcello M.G.Caramazza M.Micela G.Sciortino S.Drake J.J.,Prisinzano L.2013-02-20T22:38:36Z2012-11-16T09:06:12ZCDS support team

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

cds-question@unistra.fropen-star-clustersx-ray-sourcesMechanisms regulating the origin of X-rays in young stellar objects and the correlation with their evolutionary stage are under debate. Studies of the X-ray properties in young clusters allow us to understand these mechanisms. One ideal target for this analysis is the Eagle Nebula (M16), with its central cluster NGC 6611. At 1750pc from the Sun, it harbors 93 OB stars, together with a population of low-mass stars from embedded protostars to disk-less Class III objects, with age <=3Myr. We study an archival 78ks Chandra/ACIS-I observation of NGC 6611 and two new 80ks observations of the outer region of M16, one centered on the Column V and the other on a region of the molecular cloud with ongoing star formation. We detect 1755 point sources with 1183 candidate cluster members (219 disk-bearing and 964 disk-less). We study the global X-ray properties of M16 and compare them with those of the Orion Nebula Cluster. We also compare the level of X-ray emission of Class II and Class III stars and analyze the X-ray spectral properties of OB stars. Our study supports the lower level of X-ray activity for the disk-bearing stars with respect to the disk-less members. The X-ray luminosity function (XLF) of M16 is similar to that of Orion, supporting the universality of the XLF in young clusters. Eighty-five percent of the O stars of NGC 6611 have been detected in X-rays. With only one possible exception, they show soft spectra with no hard components, indicating that mechanisms for the production of hard X-ray emission in O stars are not operating in NGC 6611.2012ApJ...753..117Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/753/117CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/654/347 : Chandra X-ray observations in Eagle Nebula. I. (Linsky+, 2007)J/A+A/462/245 : BVI photometry in NGC 6611 (Guarcello+, 2007)J/A+A/496/453 : Photometry of candidate members of NGC6611 (Guarcello+, 2009)J/A+A/521/A18 : Blue stars with disk photometry in NGC6611 (Guarcello+, 2010)J/A+A/521/A61 : Stars associated to Eagle Nebula (NGC6611) (Guarcello+ 2010)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/753/117https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/753/117http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/753/117https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/753/117https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/753/117http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/753/117GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/753/117/xraycat (X-ray catalog of sources in the Eagle Nebula)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/753/117/xraycat?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/753/117/xraycat?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/753/117/xraycat?GETtext/xml+votable180.050000true274.5288089-13.84050110.0055555555555555566/29461 29463 29504 29506https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/753/117?format=asciiX-raydefaultJ/ApJ/753/117/xraycatX-ray catalog of sources in the Eagle Nebulaf_logLXE[i] i for infinitymeta.codecharE_kTNE? Upper value of kTNE errorkeVstat.error;stat.maxfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[2/1924] Sequential source IDmeta.id;meta.mainintRAJ2000Right ascension (J2000.0)degpos.eq.ra;meta.mainDEJ2000Declination (J2000.0)degpos.eq.dec;meta.mainthetaC? Offset in the central observationarcminpos;arith.difffloatnullablethetaE? Offset in the east observationarcminpos;arith.difffloatnullablethetaNE? Offset in the north-east observationarcminpos;arith.difffloatnullablePnsC? Probabylity of no source associate with this position in the central observationstat.fit.goodnessfloatnullablePnsE? Probabylity of no source associate with this position in the east observationstat.fit.goodnessfloatnullablePnsNE? Probabylity of no source associate with this position in the north-east observationstat.fit.goodnessdoublenullableSigniC? Central observation source significancestat.fit.goodnessfloatnullableSigniE? East observation source significancestat.fit.goodnessfloatnullableSigniNE? North-east observation source significancestat.fit.goodnessfloatnullableClassSource classification based on optical-infrared colors (1)src.classcharTctCCentral observation total count in 0.5-8keVctphot.count;em.X-rayfloatTctEEast observation total count in 0.5-8keVctphot.count;em.X-rayfloatTctNENorth-east observation total count in 0.5-8keVctphot.count;em.X-rayfloatNctC? Central observation net count in 0.5-8keVctphot.count;em.X-rayfloatnullableNctE? East observation net count in 0.5-8keVctphot.count;em.X-rayfloatnullableNctNE? North-east observation net count in 0.5-8keVctphot.count;em.X-rayfloatnullablepsfC? Fraction of the PSF at 1.497keV corresponding to the extraction region in the central observationinstr.det.psffloatnullablepsfE? Fraction of the PSF at 1.497keV corresponding to the extraction region in the east observationinstr.det.psffloatnullablepsfNE? Fraction of the PSF at 1.497keV corresponding to the extraction region in the north-east observationinstr.det.psffloatnullableCRC? Count-rate in 0.5-8keV band in the central observationct/sphot.count;em.X-raydoublenullableCRE? Count-rate in 0.5-8keV band in the east observationct/sphot.count;em.X-raydoublenullableCRNE? Count-rate in 0.5-8keV band in the north-east observationct/sphot.count;em.X-raydoublenullableEmedC? Median photons energy in 0.5-8keV band in the central observationkeVem.energyfloatnullableEmedE? Median photons energy in 0.5-8keV band in the east observationkeVem.energyfloatnullableEmedNE? Median photons energy in 0.5-8keV band in the north-east observationkeVem.energyfloatnullableNHC? Hydrogen column density in the central observation1e+22cm**-2phys.columnDensity;obsfloatnullableE_NHC? Upper value of NHC error1e+22cm**-2stat.error;stat.maxfloatnullablee_NHC? Lower value of NHC error1e+22cm**-2stat.errorfloatnullableNHE? Hydrogen column density in the east observation1e+22cm**-2phys.columnDensity;obsfloatnullableE_NHE? Upper value of NHE error1e+22cm**-2stat.error;stat.maxfloatnullablee_NHE? lower value of NHE error1e+22cm**-2stat.errorfloatnullableNHNE? Hydrogen column density in the north-east observation1e+22cm**-2phys.columnDensity;obsfloatnullableE_NHNE? Upper value of NHNE error1e+22cm**-2stat.error;stat.maxfloatnullablee_NHNE? Lower value of NHNE error1e+22cm**-2stat.errorfloatnullablekTC? Plasma temperature in the central observationkeVphys.temperature;obsfloatnullableE_kTC? Upper value of kTC errorkeVstat.error;stat.maxfloatnullablee_kTC? Lower value of kTC errorkeVstat.errorfloatnullablekTE? Plasma temperature in the east observationkeVphys.temperature;obsfloatnullableE_kTE? Upper value of kTE errorkeVstat.error;stat.maxfloatnullablee_kTE? Lower value of kTE errorkeVstat.errorfloatnullablekTNE? Plasma temperature in the north-east observationkeVphys.temperature;obsfloatnullablee_kTNE? Lower value of kTNE errorkeVstat.errorfloatnullablelogLXC? Logarithm of the X-ray luminosity in 0.5-8keV in the central observationlog(mW.m**-2)phys.luminosity;em.X-rayfloatnullableE_logLXC? Upper value of logLXC errorlog(mW.m**-2)stat.error;stat.maxfloatnullablee_logLXC? Lower value of logLXC errorlog(mW.m**-2)stat.errorfloatnullablef_logLXC[i] i for infinitymeta.codecharlogLXE? Logarithm of the X-ray luminosity in 0.5-8keV in the east observationlog(mW.m**-2)phys.luminosity;em.X-rayfloatnullableE_logLXE? Upper value of logLXE errorlog(mW.m**-2)stat.error;stat.maxfloatnullablee_logLXE? Lower value of logLXE errorlog(mW.m**-2)stat.errorfloatnullablelogLXNE? Logarithm of the X-ray luminosity in 0.5-8keV in the north-east observationlog(mW.m**-2)phys.luminosity;em.X-rayfloatnullableE_logLXNE? Upper value of logLXNE errorlog(mW.m**-2)stat.error;stat.maxfloatnullablee_logLXNE? Lower value of logLXNE errorlog(mW.m**-2)stat.errorfloatnullablef_logLXNE[i] i for infinitymeta.codechartagLXCTag indicating whether the spectral information in the central observation have been obtained (2)meta.codeinttagLXETag indicating whether the spectral information in the east observation have been obtained (2)meta.codeinttagLXNETag indicating whether the spectral information in the north-east observation have been obtained (2)meta.codeintmodelCSpectral model used to fit the source spectrum in the central observation (3)meta.id;stat.fitcharmodelESpectral model used to fit the source spectrum in the east observation (3)meta.id;stat.fitcharmodelNESpectral model used to fit the source spectrum in the north-east observation (3)meta.id;stat.fitcharprobKSC? K-S statistic with the null hypothesis that the source is not variable in the 0.5-8keV band in central observationstat.fit.goodness;src.varfloatnullableprobKSE? K-S statistic with the null hypothesis that the source is not variable in the 0.5-8keV band in east observationstat.fit.goodness;src.varfloatnullableprobKSNE? K-S statistic with the null hypothesis that the source is not variable in the 0.5-8keV band in north-east observationstat.fit.goodness;src.varfloatnullablekT2C? Second plasma temperature in the central observation (4)keVphys.temperature;obsfloatnullableE_kT2C? Upper value of kT2C errorkeVstat.error;stat.maxfloatnullablee_kT2C? Lower value of kT2C errorkeVstat.errorfloatnullablekT2E? Second plasma temperature in the east observation(4)keVphys.temperature;obsfloatnullableE_kT2E? Upper value of kT2E errorkeVstat.error;stat.maxfloatnullablee_kT2E? Lower value of kT2E errorkeVstat.errorfloatnullablekT2NE? Second plasma temperature in the north-east observation (4)keVphys.temperature;obsfloatnullableE_kT2NE? Upper value of kT2NE errorkeVstat.error;stat.maxfloatnullablee_kT2NE? Lower value of kT2NE errorkeVstat.errorfloatnullablephC? Photon index in the central observation (5)spect.indexfloatnullableE_phC? Upper value of phC errorstat.error;stat.maxfloatnullablee_phC? Lower value of phC errorstat.errorfloatnullablephE? Photon index in the east observation (5)spect.indexfloatnullableE_phE? Upper value of phE errorstat.error;stat.maxfloatnullablee_phE? Lower value of phE errorstat.errorfloatnullablephNE? Photon index in the north-east observation (5)spect.indexfloatnullableE_phNE? Upper value of phNE errorstat.error;stat.maxfloatnullablee_phNE? Lower value of phNE errorstat.errorfloatnullable