J/ApJ/813/25ivo://CDS.VizieR/J/ApJ/813/25doi:10.26093/cds/vizier.18130025CDSSaral G.Hora J.L.Willis S.E.Koenig X.P.Gutermuth R.A.Saygac A.T.2017-10-18T08:23:45Z2016-03-11T15:31:52ZCDS support team

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

cds-question@unistra.fryoung-stellar-objectsinfrared-photometrystellar-agesWe present the initial results of our investigation of the star-forming complex W49, one of the youngest and most luminous massive star-forming regions in our Galaxy. We used Spitzer/Infrared Array Camera (IRAC) data to investigate massive star formation with the primary objective of locating a representative set of protostars and the clusters of young stars that are forming around them. We present our source catalog with the mosaics from the IRAC data. In this study we used a combination of IRAC, MIPS, Two Micron All Sky Survey, and UKIRT Deep Infrared Sky Survey (UKIDSS) data to identify and classify the young stellar objects (YSOs). We identified 232 Class 0/I YSOs, 907 Class II YSOs, and 74 transition disk candidate objects using color-color and color-magnitude diagrams. In addition, to understand the evolution of star formation in W49, we analyzed the distribution of YSOs in the region to identify clusters using a minimal spanning tree method. The fraction of YSOs that belong to clusters with >=7 members is found to be 52% for a cutoff distance of 96", and the ratio of Class II/I objects is 2.1. We compared the W49 region to the G305 and G333 star-forming regions and concluded that W49 has the richest population, with seven subclusters of YSOs.2015ApJ...813...25Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/813/25CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/328 : AllWISE Data Release (Cutri+ 2013)II/316 : UKIDSS-DR6 Galactic Plane Survey (Lucas+ 2012)II/293 : GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)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/A+A/568/L13 : K-band spectrum of the very massive star W49nr1 (Wu+, 2014)J/ApJS/212/2 : Molecular clouds in the 4th Galactic quadrant (Garcia+, 2014)J/MNRAS/437/1791 : RMS survey: molecular observations (Urquhart+, 2014)J/ApJS/209/29 : MYStIX: Mid-IR observations and catalogs (Kuhn+, 2013)J/ApJ/778/96 : Spitzer and NEWFIRM observations of NGC 6334 (Willis+, 2013)J/ApJ/773/135 : Disk-bearing stars in Cygnus OB2 (Guarcello+, 2013)J/ApJ/720/679 : Optical spectroscopy in Cygnus X region (Beerer+, 2010)J/AJ/138/1380 : Dust clumps in the Galactic Plane (Matthews+, 2009)J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)J/ApJ/688/1142 : Star formation in W5: Spitzer observations (Koenig+, 2008)J/AJ/136/2413 : Galactic midplane Spitzer red sources (Robitaille+, 2008)J/A+A/482/585 : JHK photometry of stars in Sh 2-212 (Deharveng+, 2008)J/ApJ/674/336 : Spitzer observations of NGC 1333 (Gutermuth+, 2008)J/ApJS/155/577 : H2O masers in W49 North and Sagittarius B2 (McGrath+, 2004)J/ApJ/393/149 : W49N H2O maser outflow: distance and kinematics (Winn+, 1992)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/813/25https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/813/25http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/813/25https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/813/25https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/813/25http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/813/25GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/813/25/table6 (WISE YSO source list)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/813/25/table6?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/813/25/table6?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/813/25/table6?GETtext/xml+votable180.050000true287.21520799.27377510.005555555555555556Cone search capability for table J/ApJ/813/25/table10 (Physical parameters of massive YSO candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/813/25/table10?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/813/25/table10?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/813/25/table10?GETtext/xml+votable180.050000true287.520781949.021031110.005555555555555556Cone search capability for table J/ApJ/813/25/table4 (Source list)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/813/25/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/813/25/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/813/25/table4?GETtext/xml+votable180.050000true288.4212959.0791850.0055555555555555565/7651 7654 6/30599 30610 30629 306406.772611666688002e-21 1.692669228152603e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/813/25?format=asciiInfrareddefaultJ/ApJ/813/25/table6WISE YSO source listrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension in decimal degrees from WISE (J2000) (II/328)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees from WISE (J2000) (II/328)degpos.eq.dec;meta.mainW1mag[9.1/14.1] WISE/W1 magnitude (3.35um) (II/328)magphot.mag;em.IR.3-4umfloate_W1mag[0.02/0.3] Mean error on W1mag (II/328)magstat.error;phot.magfloatW2magWISE/W2 magnitude (4.6um) (II/328)magphot.mag;em.IR.4-8umfloate_W2magMean error on W2 magnitude (4.6um) (II/328)magstat.error;phot.magfloatW3magWISE/W3 magnitude (11.6um) (II/328)magphot.flux.density;em.IR.8-15umfloate_W3magMean error on W3 magnitude (11.6um) (II/328)magstat.error;phot.magfloatW4mag[1.7/6.2] WISE/W4 magnitude (22.1um) (II/328)magphot.flux.density;em.IR.15-30umfloate_W4mag[0.02/0.08] Mean error on W4mag (II/328)magstat.error;phot.magfloatCl-W[1/2] WISE Class (1)meta.code.classintSSTOERCMatched SSTOERC Spitzer Source Name; Table 4meta.id.crosscharCl-I[1/2] IRAC Class (1)meta.code.classintWISEDisplay the WISE data (II/328) within 2"meta.ref.urlcharJ/ApJ/813/25/table10Physical parameters of massive YSO candidatesCl[1/3] Massive YSO Class (2)meta.code.classinte_Age[0/1] Uncertainty in Age1e+06yrstat.error;time.agefloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeqMassive YSO sequential running numbermeta.recordintSSTOERCSSTOERC Spitzer Source Name as in table 4meta.id;meta.maincharRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainMass[7.3/19] Stellar Mass derived from SED Fit (1)solMassphys.massfloate_Mass[0/4.4] Uncertainty in MasssolMassstat.error;phys.massfloatLum[0.7/34.4] Stellar Luminosity derived from SED Fit (1)1000solLumphys.luminosityfloate_Lum[0/23.7] Uncertainty in Lum1000solLumstat.errorfloatAge[0.02/3] Stellar Age derived from SED Fit (1)1e+06yrtime.agefloatJ/ApJ/813/25/table4Source listrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMSimbad column added by the CDSmeta.ref.urlintnullableSSTOERCIAU Designation (GLLL.llll+BB.bbbb) (1)meta.id;meta.maincharWSimbad column added by the CDSmeta.ref.urlintnullableRAJ2000[286.7/288.5] Right Ascension (J2000)degpos.eq.ra;meta.mainindexedDEJ2000[8.2/10] Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainindexedJmag[4.8/26.2]? 2MASS or UKIDSS J magnitudemagphot.mag;em.IR.Jdoublenullablee_Jmag[0.01/4]? Uncertainty in Jmagmagstat.error;phot.mag;em.IR.JfloatnullableHmag[3.5/21.6]? 2MASS or UKIDSS H magnitudemagphot.mag;em.IR.Hdoublenullablee_Hmag[0.01/3]? Uncertainty in Hmagmagstat.error;phot.mag;em.IR.HfloatnullableKsmag[3.2/23.4]? 2MASS or UKIDSS K_s_ magnitudemagphot.mag;em.IR.Kdoublenullablee_Ksmag[0.01/9.2]? Uncertainty in Ksmagmagstat.error;phot.mag;em.IR.Kfloatnullable[3.6][-62.1/22.8]? Spitzer/IRAC 3.6 micron band magnitudemagphot.mag;em.IR.3-4umdoublenullablee_[3.6][0/8.5]? Uncertainty in [3.6]magstat.errorfloatnullable[4.5][2.3/18.8]? Spitzer/IRAC 4.5 micron band magnitudemagphot.mag;em.IR.4-8umdoublenullablee_[4.5][0.002/8.7]? Uncertainty in [4.5]magstat.errorfloatnullable[5.8][-42.3/17.8]? Spitzer/IRAC 5.8 micron band magnitudemagphot.flux.density;em.IR.4-8umdoublenullablee_[5.8][0.001/9]? Uncertainty in [5.8]magstat.errorfloatnullable[8.0][1.7/17]? Spitzer/IRAC 8.0 micron band magnitudemagphot.flux.density;em.IR.8-15umdoublenullablee_[8.0][0.001/8.9]? Uncertainty in [8.0]magstat.errorfloatnullable[24][0.3/10.3]? Spitzer/MIPS 24 micron band magnitudemagphot.flux.density;em.IR.15-30umfloatnullablee_[24][0.02/0.4]? Uncertainty in [24]magstat.errorfloatnullableTypeObject Type (2)src.classintPhaseObject Phase (3)src.classintf_TypeFlag on Object Type for YSO candidates (4)meta.codecharalpha[-5.8/7.6]? SED slope {alpha}, from Ksmag to [24]spect.indexfloatnullable2MDisplay the 2MASS data (Cutri+ 2003, II/246) within 2"meta.ref.urlcharUKIDSSDisplay the UKIDSS-DR6 data (Lucas+ 2012, II/316) within 2"meta.ref.urlchar