J/ApJ/598/375ivo://CDS.VizieR/J/ApJ/598/375doi:10.26093/cds/vizier.15980375CDSSkinner S.Gagne M.Belzer E.2004-11-24T21:31:25Z2004-11-24T22:31:08ZCDS support team

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

cds-question@unistra.frstellar-associationspre-main-sequence-starsx-ray-sourcesWe present results of a sensitive 76ks Chandra observation of the young stellar cluster in NGC 2024, lying at a distance of ~415pc in the Orion B giant molecular cloud. Previous infrared observations have shown that this remarkable cluster contains several hundred embedded young stars, most of which are still surrounded by circumstellar disks. Thus, it presents a rare opportunity to study X-ray activity in a large sample of optically invisible protostars and classical T Tauri stars (CTTSs) undergoing accretion. Chandra detected 283 X-ray sources, of which 248 were identified with counterparts at other wavelengths, mostly in the near-infrared. Astrometric registration of Chandra images against the Two Micron All Sky Survey (2MASS) resulted in positional offsets of ~0.25" near field center, yielding high confidence identifications of infrared counterparts.2003ApJ...598..375Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/598/375CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/chandra : The Chandra Archive Log (CXC, 2002)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/598/375https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/598/375http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/598/375https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/598/375https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/598/375http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/598/375GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/598/375/table1 (CHANDRA X-ray Sources in NGC 2024)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/598/375/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/598/375/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/598/375/table1?GETtext/xml+votable180.050000true85.3040417-1.91666670.0055555555555555566/22854 22855https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/598/375?format=asciiX-raydefaultJ/ApJ/598/375/table1CHANDRA X-ray Sources in NGC 2024recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[SGB2003]Running object numbermeta.id;meta.mainintn_[SGB2003][*f ] Note detailed in notes.dat filemeta.notecharNameObject name (JHHMMSS.s-DDMMSS)meta.idcharRAJ2000CHANDRA Right Ascension (J2000) (2)pos.eq.ra;meta.mainDEJ2000CHANDRA Declination (J2000) (2)pos.eq.dec;meta.mainNCtsNet (0.5-7keV) counts (3)ctphot.count;em.X-rayinte_NCtsUncertainty in NCts (4)ctstat.errorintKSKolmogorov-Smirnov variability statistic (5)stat.fit.paramfloatEMean (0.5-7keV) photon energykeVem.energyfloatNH? Hydrogen absorption column density (6)1e+22cm**-2phys.columnDensityfloatnullableE_NH? Upper 90% confidence error on NH (7)1e+22cm**-2stat.errorfloatnullablee_NH? Lower 90% confidence error on NH (7)1e+22cm**-2stat.errorfloatnullablekT? Characteristic plasma temperature (6)keVphys.temperaturefloatnullableE_kT? Upper 90% confidence error on kT (7)keVstat.errorfloatnullablee_kT? Lower 90% confidence error on kT (7)keVstat.errorfloatnullableFX,absThe absorbed (0.5-7keV) flux in units of erg/cm^2^/s (8)mW.m**-2phot.flux;em.X-raydoublelogLx? Log of the (0.5-7keV) unabsorbed luminosity in units of erg/s (9)log(1e-07W)phys.luminosity;em.X-rayfloatnullablef_logLx[v] Indicates a variable logLxmeta.code.errorcharIDCandidate IR, optical or radio identification (10)meta.id.crosscharJ/ApJ/598/375/notesNotesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNoteNote codemeta.notecharTextText of the notemeta.note