J/ApJ/706/83ivo://CDS.VizieR/J/ApJ/706/83doi:10.26093/cds/vizier.17060083CDSKang M.Bieging J.H.Povich M.S.Lee Y.2026-05-19T14:25:37Z2012-01-05T12:12:26ZCDS support team

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

cds-question@unistra.frh-ii-regionsinfrared-photometryyoung-stellar-objectsmolecular-cloudsWe present 737 candidate young stellar objects (YSOs) near the W51 giant molecular cloud over an area of 1.25x1.00{deg} selected from Spitzer Space Telescope data. We use spectral energy distribution fits to identify YSOs and distinguish them from main-sequence (MS) or red giant stars, asymptotic giant branch stars, and background galaxies. Based on extinction of each YSO, we separate a total of 437 YSOs associated with the W51 region from the possible foreground sources. We identify 69 highly embedded Stage 0/I candidate YSOs in our field with masses >5M_{sun}_ (corresponding to mid- to early-B MS spectral types), 46 of which are located in the central active star-forming regions of W51A and W51B. From the YSOs associated with W51, we find evidence for mass segregation showing that the most massive YSOs are concentrated on the W51 HII region complex.2009ApJ...706...83Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/706/83CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/293 : GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)V/112 : Catalog of Star-Forming Regions in the Galaxy (Avedisova, 2002)J/ApJS/191/232 : CO survey of W51 molecular cloud (Bieging+, 2010)J/ApJ/685/1005 : Spitzer and high-mass star forming regions (Qiu+, 2008)J/MNRAS/353/1025 : JHK photometry of 4 W51 star clusters (Nanda+, 2004)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/706/83https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/706/83http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/706/83https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/706/83https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/706/83http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/706/83GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/706/83/ysos (Magnitudes and model parameters of YSO candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/706/83/ysos?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/706/83/ysos?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/706/83/ysos?GETtext/xml+votable180.050000true290.79995213.7470190.0055555555555555565/7673 6/306916.772611666688002e-21 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/706/83?format=asciiInfrareddefaultJ/ApJ/706/83/ysosMagnitudes and model parameters of YSO candidatesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqRunning index number (<[KBP2009] NNN> in Simbad)meta.idintf_Seq[*] *: Strange upper and lower values for this object; take with caution (flag added by CDS)meta.codecharSSTGLMCSource name (GLLL.llll+BB.bbbb)meta.id;meta.maincharb_AVLower 68% (or 95%) probability limit in AVmagstat.errorfloatAVAverage V band extinctionmagphys.absorptionfloatn_AV[*] Range on AV is 95% probabilitymeta.notecharB_AVUpper 68% (or 95%) probability limit in AVmagstat.errorfloatb_MstarLower 68% (or 95%) probability limit in MstarsolMassstat.errorfloatMstarAverage central star masssolMassphys.massfloatn_Mstar[*] Range on Mstar is 95% probabilitymeta.notecharB_MstarUpper 68% (or 95%) probability limit in MstarsolMassstat.errorfloatb_LtotLower 68% (or 95%) probability limit in LTotsolLumstat.errorintLtotAverage total luminositysolLumphys.luminosity;em.IRintn_Ltot[*] Range on Ltot is 95% probabilitymeta.notecharB_LtotUpper 68% (or 95%) probability limit in LTotsolLumstat.errorintStgEvolutionary stage (Amb: Ambiguous source)src.classcharCl1YSO class based on IRAC data (2)src.classcharCl2YSO class based on the spectral slope {alpha} i between 2 and 24um (2)src.classcharJmag? 2MASS J band magnitudemagphot.mag;em.IR.JfloatnullableHmag? 2MASS H band magnitudemagphot.mag;em.IR.HfloatnullableKsmag? 2MASS K_s_ band magnitudemagphot.mag;em.IR.Kfloatnullable[3.6]? Spitzer/IRAC 3.6 micron filter magnitudemagphot.mag;em.IR.3-4umfloatnullable[4.5]? Spitzer/IRAC 4.5 micron filter magnitudemagphot.mag;em.IR.4-8umfloatnullable[5.8]? Spitzer/IRAC 5.8 micron filter magnitudemagphot.flux.density;em.IR.4-8umfloatnullable[8.0]? Spitzer/IRAC 8.0 micron filter magnitudemagphot.flux.density;em.IR.8-15umfloatnullable[24]? Spitzer/MIPS 24 micron filter magnitudemagphot.flux.density;em.IR.15-30umfloatnullableA[W/F] W=Associated with W51, or F=foreground by A_V_meta.code.memberchar2MDisplay the 2MASS data (Cutri et al. 2003, Cat. II/246)meta.ref.urlcharSimbadSimbad column added by the CDSmeta.refchar_GlonPositions from SSTGLMC name (longitude part)degpos.galactic.lon_GlatPositions from SSTGLMC name (latitude part)degpos.galactic.lat