J/ApJ/839/108ivo://CDS.VizieR/J/ApJ/839/108doi:10.26093/cds/vizier.18390108CDSSaral G.Hora J.L.Audard M.Koenig X.P.Martinez-Galarza J.R.,Motte F.Nguyen-Luong Q.Saygac A.T.Smith H.A.2020-01-28T14:36:31Z2018-01-16T15:44:15ZCDS support team

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

cds-question@unistra.frinfrared-photometryyoung-stellar-objectsstellar-massesWe present the results of our investigation of the star-forming complexes W51 and W43, two of the brightest in the first Galactic quadrant. In order to determine the young stellar object (YSO) populations in W51 and W43 we used color-magnitude relations based on Spitzer mid-infrared and 2MASS/UKIDSS near- infrared data. We identified 302 Class I YSOs and 1178 Class II/transition disk candidates in W51, and 917 Class I YSOs and 5187 Class II/transition disk candidates in W43. We also identified tens of groups of YSOs in both regions using the Minimal Spanning Tree (MST) method. We found similar cluster densities in both regions, even though Spitzer was not able to probe the densest part of W43. By using the Class II/I ratios, we traced the relative ages within the regions and, based on the morphology of the clusters, we argue that several sites of star formation are independent of one another in terms of their ages and physical conditions. We used spectral energy distribution- fitting to identify the massive YSO (MYSO) candidates since they play a vital role in the star formation process, and then examined them to see if they are related to any massive star formation tracers such as UCH II regions, masers, or dense fragments. We identified 17 MYSO candidates in W51, and 14 in W43, respectively, and found that groups of YSOs hosting MYSO candidates are positionally associated with H II regions in W51, though we do not see any MYSO candidates associated with previously identified massive dense fragments in W43.2017ApJ...839..108Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/839/108CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)II/316 : UKIDSS-DR6 Galactic Plane Survey (Lucas+ 2012)VIII/64 : Westerhout's Catalog of Discrete Sources (Westerhout, 1958)VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)J/A+A/371/497 : OB associations in spiral gal. NGC 300 (Pietrzynski+, 2001)J/A+A/440/121 : K magnitudes of OB stars in UCHIIs (Bik+, 2005)J/A+A/476/1243 : Millimeter continuum mapping of Cygnus X (Motte+, 2007)J/ApJ/669/327 : S3MC: YSOs in N66, in SMC (Simon+, 2007)J/ApJ/674/336 : Spitzer observations of NGC 1333 (Gutermuth+, 2008)J/ApJ/688/1142 : Star formation in W5: Spitzer observations (Koenig+, 2008)J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)J/ApJ/706/83 : Embedded YSO candidates in W51 (Kang+, 2009)J/ApJ/720/679 : Optical spectroscopy in Cygnus X region (Beerer+, 2010)J/ApJ/720/1055 : VBLA observations of W51 Main/South (Sato+, 2010)J/ApJ/727/64 : Young stellar groups & their most massive stars (Kirk+, 2011)J/A+A/525/A149 : Red MSX Survey (RMS): bol. fluxes of YSOs (Mottram+, 2011)J/ApJ/752/127 : IR observations of AFGL 490 (Masiunas+, 2012)J/A+A/560/A24 : IRAM 30m CO-observations in W43 (Carlhoff+, 2013)J/AJ/148/11 : Infrared photometry in Cygnus-X (Kryukova+, 2014)J/AJ/150/95 : Masses and ages of YSOs in Per OB2 (Azimlu+, 2015)J/AJ/149/64 : MIPSGAL 24{mu}m point source catalog (Gutermuth+, 2015)J/ApJ/813/25 : YSO candidates in W49 observed with Spitzer (Saral+, 2015)J/ApJ/827/96 : WISE census of YSOs in Canis Major (Fischer+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/839/108https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/839/108http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/839/108https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/839/108https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/839/108http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/839/108GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/839/108/clusters (Properties of the clusters in W51 and W43 (tables 6 and 7))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/839/108/clusters?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/839/108/clusters?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/839/108/clusters?GETtext/xml+votable180.050000true290.6281611114.1211850.005555555555555556Cone search capability for table J/ApJ/839/108/w51cat (W51 Spitzer 2MASS/UKIDSS final catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/839/108/w51cat?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/839/108/w51cat?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/839/108/w51cat?GETtext/xml+votable180.050000true290.1195713.490110.005555555555555556Cone search capability for table J/ApJ/839/108/mysos (Physical parameters of massive YSO candidates in W51 and W43 (tables 10 and 11))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/839/108/mysos?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/839/108/mysos?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/839/108/mysos?GETtext/xml+votable180.050000true290.2522580614.780608060.005555555555555556Cone search capability for table J/ApJ/839/108/w43cat (W43 Spitzer 2MASS/UKIDSS final catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/839/108/w43cat?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/839/108/w43cat?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/839/108/w43cat?GETtext/xml+votable180.050000true281.04041-3.214720.0055555555555555565/7565 7567 7673 6/30257 30258 30259 30265 30306 30312 30670 30689 30691 307006.772611666688002e-21 1.692669228152603e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/839/108?format=asciiInfrareddefaultJ/ApJ/839/108/clustersProperties of the clusters in W51 and W43 (tables 6 and 7)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegName of the star-forming complexobs.fieldcharGroup[1/95] Group running numbermeta.id;meta.mainintm_Group[a-g*] SubGroup letter code (1)meta.code.multipcharRAJ2000Right ascension in decimal degrees (J2000) (2)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000) (2)degpos.eq.dec;meta.mainNir[10/3047] Number of IR excess sources in group/subgroup (3)meta.numberintNI[0/561] Number of Class I candidatesmeta.numberintNII[4/2358] Number of Class II candidatesmeta.numberintII/I[0.5/21]? Class II to Class I ratiometa.numberfloatnullablee_II/I[0.2/29]? Uncertainty in II/Istat.errorfloatnullableNp[0/73] Number of deeply embedded protostar candidatesmeta.numberintNt[0/55] Number of transition disk candidatesmeta.numberintNm[0/11]? Number of massive YSO candidatesmeta.numberintnullableDiam[28/1255] Group/SubGroup diameterarcsecphys.angSizefloate_Diam[0.7/143] Uncertainty in Diamarcsecstat.errorfloatJ/ApJ/839/108/w51catW51 Spitzer 2MASS/UKIDSS final catalogalpha[-4.2/7.2]? SED slope {alpha}spect.indexfloatnullableClass[-100/99] Classification type (2)meta.code.classintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSSTOERCSpitzer identifier (GLLL.llll+B.bbbb) (1)meta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainindexedDEJ2000Declination (J2000)degpos.eq.dec;meta.mainindexedJmag[-10/25.9]?=- 2MASS/UKIDSS J-band magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag[0.02/55]? Jmag uncertaintymagstat.error;phot.mag;em.IR.JfloatnullableHmag[-10/24.5]?=- 2MASS/UKIDSS H-band magnitudemagphot.mag;em.IR.Hfloatnullablee_Hmag[0.01/26]? Hmag uncertaintymagstat.error;phot.mag;em.IR.HfloatnullableKmag[-10/24.5]?=- 2MASS/UKIDSS K-band magnitudemagphot.mag;em.IR.Kfloatnullablee_Kmag[0.01/79]? Kmag uncertaintymagstat.error;phot.mag;em.IR.Kfloatnullable[3.6][-10/19]?=- Spitzer/IRAC 3.6um magnitudemagphot.mag;em.IR.3-4umdoublenullablee_[3.6][0/9]? [3.6] uncertaintymagstat.errorfloatnullable[4.5][-154/19.1]?=- Spitzer/IRAC 4.5um magnitudemagphot.mag;em.IR.4-8umdoublenullablee_[4.5][0.001/9]? [4.5] uncertaintymagstat.errorfloatnullable[5.8][-188/17.5]?=- Spitzer/IRAC 5.8um magnitudemagphot.flux.density;em.IR.4-8umdoublenullablee_[5.8][0.001/9]? [5.8] uncertaintymagstat.errorfloatnullable[8.0][-10/17.1]?=- Spitzer/IRAC 8.0um magnitudemagphot.flux.density;em.IR.8-15umdoublenullablee_[8.0][0.001/9]? [8.0] uncertaintymagstat.errorfloatnullable[24][0.1/10.1]? Spitzer/MIPS 24um magnitudemagphot.flux.density;em.IR.15-30umfloatnullablee_[24][0.02/0.4]? [24] uncertaintymagstat.errorfloatnullablen_Class[1/2] Method by which they were classified (3)meta.noteinte_alpha[0/4]? alpha uncertaintystat.error;pos.eq.rafloatnullableR2[0/1]? R-squared valuestat.fit.paramfloatnullable2MDisplay the 2MASS data (Cutri+ 2003, II/246) within 1.5" if Jmag is filledmeta.ref.urlcharUKIDSSDisplay the UKIDSS-DR9 data (Lawrence+ 2012, II/319) within 1.2" if Kmag is filledmeta.ref.urlcharGLIMPSEDisplay the GLIMPSE data (II/293) within 1.5"meta.ref.urlcharJ/ApJ/839/108/mysosPhysical parameters of massive YSO candidates in W51 and W43 (tables 10 and 11)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegName of the star-forming complexobs.fieldcharSeq[1/17] Massive YSO Sequential running numbermeta.recordintf_SeqFlag on Seq; (*) source has 24 micron datameta.codecharSSTOERCIAU name (GLLL.llll+B.bbbb)meta.id;meta.maincharRAJ2000Right ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainLum[1/10] MYSO Luminosity1000solLumphys.luminosity;em.IRfloate_Lum[0/4] Uncertainty in Lum (1)1000solLumstat.errorfloatMass[5/12] MYSO MasssolMassphys.massfloate_Mass[0/3] Uncertainty in Mass (1)solMassstat.error;phys.massfloatIRACIRAC population class (2)meta.code.classcharSEDSED class (2)meta.code.classcharalpha[-0.2/3] SED Slopespect.indexfloate_alpha[0.06/1.2] Uncertainty in alphastat.error;pos.eq.rafloatSimbadSimbad column added by the CDSmeta.ref.urlcharJ/ApJ/839/108/w43catW43 Spitzer 2MASS/UKIDSS final catalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSSTOERCSpitzer identifier (GLLL.llll+B.bbbb) (1)meta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainindexedDEJ2000Declination (J2000)degpos.eq.dec;meta.mainindexedJmag[-10/25.9]?=- 2MASS/UKIDSS J-band magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag[0.02/55]? Jmag uncertaintymagstat.error;phot.mag;em.IR.JfloatnullableHmag[-10/24.5]?=- 2MASS/UKIDSS H-band magnitudemagphot.mag;em.IR.Hfloatnullablee_Hmag[0.01/26]? Hmag uncertaintymagstat.error;phot.mag;em.IR.HfloatnullableKmag[-10/24.5]?=- 2MASS/UKIDSS K-band magnitudemagphot.mag;em.IR.Kfloatnullablee_Kmag[0.01/79]? Kmag uncertaintymagstat.error;phot.mag;em.IR.Kfloatnullable[3.6][-10/19]?=- Spitzer/IRAC 3.6um magnitudemagphot.mag;em.IR.3-4umdoublenullablee_[3.6][0/9]? [3.6] uncertaintymagstat.errorfloatnullable[4.5][-154/19.1]?=- Spitzer/IRAC 4.5um magnitudemagphot.mag;em.IR.4-8umdoublenullablee_[4.5][0.001/9]? [4.5] uncertaintymagstat.errorfloatnullable[5.8][-188/17.5]?=- Spitzer/IRAC 5.8um magnitudemagphot.flux.density;em.IR.4-8umdoublenullablee_[5.8][0.001/9]? [5.8] uncertaintymagstat.errorfloatnullable[8.0][-10/17.1]?=- Spitzer/IRAC 8.0um magnitudemagphot.flux.density;em.IR.8-15umdoublenullablee_[8.0][0.001/9]? [8.0] uncertaintymagstat.errorfloatnullable[24][0.1/10.1]? Spitzer/MIPS 24um magnitudemagphot.flux.density;em.IR.15-30umfloatnullablee_[24][0.02/0.4]? [24] uncertaintymagstat.errorfloatnullableClass[-100/99] Classification type (2)meta.code.classintn_Class[1/2] Method by which they were classified (3)meta.noteintalpha[-4.2/7.2]? SED slope {alpha}spect.indexfloatnullablee_alpha[0/4]? alpha uncertaintystat.error;pos.eq.rafloatnullableR2[0/1]? R-squared valuestat.fit.paramfloatnullable2MDisplay the 2MASS data (Cutri+ 2003, II/246) within 1.5" if Jmag is filledmeta.ref.urlcharUKIDSSDisplay the UKIDSS-DR9 data (Lawrence+ 2012, II/319) within 1.2" if Kmag is filledmeta.ref.urlcharGLIMPSEDisplay the GLIMPSE data (II/293) within 1.5"meta.ref.urlchar