J/ApJ/880/9ivo://CDS.VizieR/J/ApJ/880/9doi:10.26093/cds/vizier.18800009CDSWinston E.Hora J.Gutermuth R.Tolls V.2022-04-04T09:09:00Z2021-01-20T11:56:56ZCDS support team

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

cds-question@unistra.frinfrared-photometryyoung-stellar-objectsstellar-spectral-typesstellar-agesgalaxy-planesmilky-way-galaxyIn this paper we undertake a study of the 21deg^2^ SMOG field, a Spitzer cryogenic mission Legacy program to map a region of the outer Milky Way toward the Perseus and outer spiral arms with the IRAC and MIPS instruments. We identify 4648 YSOs across the field. Using the DBSCAN method, we identify 68 clusters or aggregations of YSOs in the region, having eight or more members. We identify 1197 Class I objects, 2632 Class II objects, and 819 Class III objects, of which 45 are candidate transition disk objects, utilizing the MIPS 24 photometry. The ratio of YSOs identified as members of clusters was 2872/4648, or 62%. The ratios of Class I to Class II YSOs in the clusters are broadly consistent with those found in the inner Galactic and nearby Gould Belt young star formation regions. The clustering properties indicate that the protostars may be more tightly bound to their natal sites than the Class II YSOs, and the Class III YSOs are generally widely distributed. We further perform an analysis of the WISE data of the SMOG field to determine how the lower resolution and sensitivity of WISE affects the identification of YSOs as compared to Spitzer: we identify 931 YSOs using combined WISE and 2MASS photometry, or 20% (931/4648) of the total number identified with Spitzer. Performing the same clustering analysis finds 31 clusters that reliably trace the larger associations identified with the Spitzer data. Twelve of the clusters identified have previously measured distances from the WISE HII survey. SEDFitter modeling of these YSOs is reported, leading to an estimation of the initial mass function in the aggregate of these clusters that approximates that found in the inner Galaxy, implying that the processes behind stellar mass distribution during star formation are not widely affected by the lower density and metallicity of the outer Galaxy.2019ApJ...880....9Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/880/9CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)II/293 : GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)II/328 : AllWISE Data Release (Cutri+ 2013)J/ApJ/669/493 : Spitzer/Chandra YSOs in Serpens cloud core (Winston+, 2007)J/ApJ/674/336 : Spitzer observations of NGC 1333 (Gutermuth+, 2008)J/AJ/136/2413 : Galactic midplane Spitzer red sources (Robitaille+, 2008)J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)J/AJ/137/4810 : LMC-SAGE AGB star candidates (Srinivasan+, 2009)J/AJ/140/266 : NGC 1333 X-ray luminous YSOs properties (Winston+, 2010)J/ApJ/743/166 : X-ray and infra-red study of RCW 38 (Winston+, 2011)J/MNRAS/430/1125 : RMS survey: NIR spectroscopy of massive YSOs (Cooper+, 2013)J/ApJS/212/1 : The WISE catalog of Galactic HII regions (Anderson+, 2014)J/ApJS/220/11 : SEDs of Spitzer YSOs in the Gould Belt (Dunham+, 2015)J/ApJ/827/96 : WISE census of YSOs in Canis Major (Fischer+, 2016)J/ApJ/839/108 : YSOs in the star-forming regions W51 & W43 (Saral+, 2017)J/A+A/620/A27 : Taurus ultra-wide pairs. II. (Joncour+, 2018)J/ApJS/240/26 : YSO cand. in Canis Major OB1 association (Sewilo+, 2019)http://irsa.ipac.caltech.edu/data/SPITZER/GLIMPSE/overview.html : Spitzer datahttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/880/9https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/880/9http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/880/9https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/880/9https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/880/9http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/880/9GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/880/9/table1 (SMOG field young stellar objects: photometry table)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/880/9/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/880/9/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/880/9/table1?GETtext/xml+votable180.050000true338.8650761159.394053060.005555555555555556Cone search capability for table J/ApJ/880/9/table3 (SMOG field young stellar objects: clusters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/880/9/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/880/9/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/880/9/table3?GETtext/xml+votable180.050000true339.0310115359.48700411520.005555555555555556Cone search capability for table J/ApJ/880/9/table7 (SMOG field young stellar objects: WISE photometry)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/880/9/table7?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/880/9/table7?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/880/9/table7?GETtext/xml+votable180.050000true341.565345162.15446010.0055555555555555565/3567 3578 3905 3907-3910 6/14254-14255 14266-14267 14307 15619 15625-15627 15644-15646 15648-15649 15652 15680-15682 156886.772611666688002e-21 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/880/9?format=asciiInfrareddefaultJ/ApJ/880/9/table1SMOG field young stellar objects: photometry tableSimbadSimbad column added by the CDSmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFieldSMOG field identifier (SRC0 to SRC4647)meta.id;obs.fieldcharIDGLIMPSE identifier from SMOG Archive (GLLL.llll+BB.bbbb)meta.id;meta.maincharprimaryRAJ2000[327.96/346.45] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[56.49/62.34] Declination (J2000)degpos.eq.dec;meta.mainI-Det[0/1] IRAC photometry selection code (1=selected)meta.codeintM-Det[0/1] MIPS photometry selection code (1=selected)meta.codeintU-Det[0/1] UKIRT photometry selection code (1=selected)meta.codeintJ2mag[5.63/17.26]? 2MASS J band magnitudemagphot.mag;em.IR.Jfloatnullablee_J2mag[0.018/0.53]? Uncertainty in J2magmagstat.error;phot.magfloatnullableH2mag[4.58/16.2]? 2MASS H band magnitudemagphot.mag;em.IR.Hfloatnullablee_H2mag[0.017/0.27]? Uncertainty in H2magmagstat.error;phot.magfloatnullableKs2mag[3.99/15.78]? 2MASS Ks band magnitudemagphot.mag;em.IR.Kfloatnullablee_Ks2mag[0.015/10]? Uncertainty in Ks2magmagstat.error;phot.magfloatnullableJUmag[0/20.23]? UKIRT J band magnitudemagphot.mag;em.IR.Jfloatnullablee_JUmag[0/0.3]? Uncertainty in JUmagmagstat.error;phot.magfloatnullableHUmag[0/19.4]? UKIRT H band magnitudemagphot.mag;em.IR.Hfloatnullablee_HUmag[0/0.2]? Uncertainty in HUmagmagstat.error;phot.magfloatnullableKUmag[9/18]? UKIRT K band magnitudemagphot.mag;em.IR.Kfloatnullablee_KUmag[0.001/0.2]? Uncertainty in KUmagmagstat.error;phot.magfloatnullable3.6mag[3.6/17.5]? Spitzer/IRAC 3.6um magnitudemagphot.mag;em.IR.3-4umfloatnullablee_3.6mag[0.02/0.3]? Uncertainty in 3.6magmagstat.errorfloatnullable4.5mag[3.6/16.7]? Spitzer/IRAC 4.5um magnitudemagphot.mag;em.IR.4-8umfloatnullablee_4.5mag[0.015/0.21]? Uncertainty in 4.5magmagstat.errorfloatnullable5.8mag[3.3/15]? Spitzer/IRAC 5.8um magnitudemagphot.flux.density;em.IR.4-8umfloatnullablee_5.8mag[0.014/0.21]? Uncertainty in 5.8magmagstat.errorfloatnullable8.0mag[3.1/14.1]? Spitzer/IRAC 8um magnitudemagphot.flux.density;em.IR.8-15umfloatnullablee_8.0mag[0.013/0.22]? Uncertainty in 8.0magmagstat.errorfloatnullable24mag[0.37/11.4]? Spitzer/MIPS 24um band magnitudemagphot.flux.density;em.IR.15-30umfloatnullablee_24mag[0/0.61]? Uncertainty in 24magmagstat.errorfloatnullablealpha-I[-11/14.1] SED slope from IRAC photometryspect.indexfloatalpha-M[-11/14.1] SED slope from IRAC+MIPS photometryspect.indexfloatClass-I[1/3] Evolutionary class: IRAC bandsmeta.code.classfloatClass-M[1/3] Evolutionary class: IRAC+MIPS bandsmeta.code.classfloatClass-T[0/2.3] Evolutionary class: Transition Disk Candidatemeta.code.classfloatSeq[0/67]? Number of cluster (as in Table 3) containing YSOmeta.numberintnullableSubC[0/16]? Number of subcluster containing YSOmeta.idintnullableSEDDisplay the SED results (link to Table 5)meta.ref.urlintnullableWISEDisplay the WISE photometry for this source (link to Table 7)meta.ref.urlintnullable2MASS2MASS identifier (HHMMSSss+DDMMSSs; J2000) if anymeta.id.crosscharMatchSIMBAD matches (before July 2019) within 1" (link to Table 2)meta.ref.urlcharJ/ApJ/880/9/table2SMOG field young stellar objects: SIMBAD matches within 1 arcsecIDGLIMPSE identifier from SMOG Archive (GLLL.llll+BB.bbbb)meta.id;meta.maincharSimbadSimbad identifiermeta.id.assoccharFieldSMOG field identifiermeta.id;obs.fieldcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintOTypeSimbad object classification typemeta.code.class;src.classcharSpTypeSimbad spectral typesrc.spTypecharJ/ApJ/880/9/table3SMOG field young stellar objects: clustersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[0/67] Internal cluster index numberspect.indexintNameCluster identifier (GLLL.ll+B.bb)meta.id;meta.maincharYSO[8/428] Number of YSOs in the clustermeta.numberintSubC[0/17] Subcluster numbermeta.idintRAJ2000[328.18/346.17] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[57.5/62.1] Declination (J2000)degpos.eq.dec;meta.mainRad[0.03/0.81] Circular radiusdegphys.angSizefloatLen[0.01/0.08] Branch lengthdegphys.angSize;srcfloatWISEWISE H II sources (1)meta.id.assocJ/ApJ/880/9/table5SMOG field young stellar objects: SED fitter resultsL*[0.2/3961] Stellar total luminositysolLumphys.luminositydoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[0/66] Cluster number as in Table 3meta.recordintnullableDist[2.5/7.8] Distancekpcpos.distance;pos.heliocentricfloatNp[3/8] Number of data pointsmeta.numberintchi2[0/3] Model {chi}^2^ valuestat.fit.chi2floate_chi2[0/3] Lower uncertainty in chi2stat.errorfloatE_chi2[8.9/26.7] Upper uncertainty in chi2stat.error;stat.maxfloatAv[0/40] Extinction in the V bandmagphys.absorptionfloate_Av[0/24.63] Lower uncertainty in Avmagstat.errorfloatE_Av[5.3/40] Upper uncertainty in Avmagstat.error;stat.maxfloatM*[0.1/13.6] Stellar masssolMassphys.massfloate_M*[0.1/5.2] Lower uncertainty in M*solMassstat.errorfloatE_M*[1.2/27.4] Upper uncertainty in M*solMassstat.error;stat.maxfloatAge[1078/9891000] Ageyrtime.agedoublee_Age[1008/1523000] Lower uncertainty in Ageyrstat.error;time.agedoubleE_Age[212500/9988000] Upper uncertainty in Ageyrstat.error;stat.maxdoubleMd[3.5e-9/0.21] Disk masssolMassphys.massdoublee_Md[0/0.0012] Lower uncertainty in MdsolMassstat.errordoubleE_Md[0.0019/1.3] Upper uncertainty in MdsolMassstat.error;stat.maxdoubleMenv[1.3/18.1]? Stellar envelope masssolMassphys.massdoublenullablee_Menv[1.1/5.7]? Lower uncertainty in MenvsolMassstat.errordoublenullableE_Menv[3.8/30.2] Upper uncertainty in MenvsolMassstat.error;stat.maxdoubleMdot[0/0.005] Accretion ratesolMass/yrarith.ratedoublee_Mdot[0/2.5e-05] Lower uncertainty in MdotsolMass/yrstat.errordoubleE_Mdot[0/0.009] Upper uncertainty in MdotsolMass/yrstat.error;stat.maxdoubleT*[2626/21850] Stellar temperatureKphys.temperaturedoublee_T*[2536/10800] Lower uncertainty in T*Kstat.errordoubleE_T*[4430/30680] Upper uncertainty in T*Kstat.error;stat.maxdoublee_L*[0.07/529] Lower uncertainty in L*solLumstat.errordoubleE_L*[2.9/30990] Upper uncertainty in L*solLumstat.error;stat.maxdoubleFieldSMOG Field ID (SRC6 to SRC4634)meta.id;obs.fieldcharJ/ApJ/880/9/table7SMOG field young stellar objects: WISE photometryrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintWISEWISE identifier (JHHMMSS.ss+DDMMSS.s)meta.id.crosscharIDGLIMPSE identifier from SMOG Archive (GLLL.llll+BB.bbbb)meta.id;meta.maincharRAJ2000[328.54/346.54] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[56.49/62.3] Declination (J2000)degpos.eq.dec;meta.mainJ2mag[7.271/18.63]? 2MASS J band magnitudemagphot.mag;em.IR.Jfloatnullablee_J2mag[0.018/0.3]? Uncertainty in J2magmagstat.error;phot.magfloatnullableH2mag[5.9/17.2]? 2MASS H band magnitudemagphot.mag;em.IR.Hfloatnullablee_H2mag[0.015/0.4]? Uncertainty in H2magmagstat.error;phot.magfloatnullableKs2mag[5.3/15.4]? 2MASS Ks band magnitudemagphot.mag;em.IR.Kfloatnullablee_Ks2mag[0.015/0.2]? Uncertainty in Ks2magmagstat.error;phot.magfloatnullable3.5mag[5/15.3] WISE W1 (3.5 micron) band magnitudemagphot.mag;em.IR.3-4umfloate_3.5mag[0.01/0.3] Uncertainty in 3.5magmagstat.errorfloat4.6mag[3.74/13.6] WISE W2 (4.6 micron) band magnitudemagphot.mag;em.IR.4-8umfloate_4.6mag[0.007/0.2] Uncertainty in 4.6magmagstat.errorfloat12mag[1.13/10] WISE W3 (12 micron) band magnitudemagphot.flux.density;em.IR.8-15umfloate_12mag[0.006/0.51] Uncertainty in 12magmagstat.errorfloat22mag[-1.51/9.2] WISE W4 (22 micron) band magnitudemagphot.flux.density;em.IR.15-30umfloate_22mag[0.005/0.5]? Uncertainty in 22magmagstat.errorfloatnullableClass[1/2.3] Evolutionary classificationmeta.code.classfloatIRAC[0/1] Also detected as an IRAC source (1=yes)meta.codefloatPhotDisplay the photometry data from Table 1 for this sourcemeta.ref.urlintnullable