J/A+A/355/651ivo://CDS.VizieR/J/A+A/355/651doi:10.26093/cds/vizier.33550651CDSFlaccomio E.Micela G.Sciortino S.Damiani F.Favata F.,Harnden F.R.JrSchachter J.2007-03-07T20:20:21Z2007-03-07T21:18:47ZCDS 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-sourcesWe analyze six ROSAT HRI observations pointed toward the Star Forming Region (SFR) NGC 2264. Three are pointed to the southern star formation core, the other three about 20' to the north. We detect 169 X-ray sources, ~95% of which are likely to be Pre Main Sequence (PMS) stars, significantly enlarging the known population of the SFR in the area covered by the observations. Using published BVRI photometry we place the X-ray sources with well defined optical counterparts on the HRI diagram and estimate their masses and ages. Our comparison of the mass function and age distribution of the X-ray sources with results previously obtained for NGC 2264, demonstrates that deep X-ray observations provide, at least in this case, a very efficient method of selecting SFR members and does not introduce stronger biases than other methods.2000A&A...355..651Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/355/651CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toIX/28 : ROSAT HRI Pointed Observations (1RXH) (ROSAT Team, 2000)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/355/651https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/355/651http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/355/651https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/355/651https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/355/651http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/355/651GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/355/651/table3 (List of detected X-ray sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/355/651/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/355/651/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/355/651/table3?GETtext/xml+votable180.050000true100.0241679.5972780.0055555555555555566/23636-23637 23639https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/355/651?format=asciiX-raydefaultJ/A+A/355/651/table3List of detected X-ray sourcesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[FMS2000]Source name ([FMS2000] XNNN in Simbad)meta.id;meta.mainintn_[FMS2000][*] *: denotes unique counterpartsmeta.notecharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainCRMaxMaximum count ratect/ksphot.count;em.X-rayfloate_CRMaxrms uncertainty on CRMaxct/ksstat.errorfloatl_CRMinLimit flag on CRMinmeta.code.errorcharCRMinMinimum count ratect/ksphot.count;em.X-rayfloate_CRMin? rms uncertainty on CRMinct/ksstat.errorfloatnullablel_<logLX>Limit flag on <logLX>meta.code.errorchar<logLX>Maximum likelihood X-ray luminositylog(1e-07W)phys.luminosity;em.X-rayfloatSNRSignifiance of source detectionstat.likelihood;obsfloatPvar? Probability of the source being variablestat.fit.goodness;src.varintnullableIdentSuggested optical counterparts (1)meta.id.assoccharJ/A+A/355/651/table4Counterparts of uniquely identified X-ray sourcesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordint[FMS2000]Source name ([FMS2000] XNNN in Simbad)meta.id;meta.mainintVmag? V magnitudemagphot.mag;em.opt.Vfloatnullablen_Vmag[ab] V magnitude origin if not that specified in Ref (1)meta.notecharB-V? B-V colour indexmagphot.color;em.opt.B;em.opt.Vfloatnullablen_B-V[ab] B-V colour origin if not that specified in Ref (1)meta.notecharV-I? V-I colour indexmagphot.color;em.opt.V;em.opt.Ifloatnullablen_V-I[bc] V-I colour origin if not that specified in Ref (1)meta.notecharSpTypeMK spectral typesrc.spTypecharn_SpType[b] Spectral type origin if not that specified in Ref (1)meta.notecharlogTeff? Effective temperaturelog(K)phys.temperature.effectivefloatnullablelog(Lbol)? Bolometric luminositylog(solLum)phys.luminosityfloatnullableRef[SF] Reference for reported photometry (1)meta.bibchar