J/MNRAS/490/832ivo://CDS.VizieR/J/MNRAS/490/832doi:10.26093/cds/vizier.74900832CDSJones O.C.Sharp M.J.Reiter M.Hirschauer A.S.Meixner M.,Srinivasan S.2024-08-20T20:14:21Z2023-02-17T13:28:56ZCDS support team

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

cds-question@unistra.fryoung-stellar-objectsstar-forming-regionspre-main-sequence-starsgalaxiesinfrared-photometrystellar-radiieffective-temperatureWe present a comprehensive study of massive young stellar objects (YSOs) in the metal-poor galaxy NGC 6822 using IRAC and MIPS data obtained from the Spitzer Space Telescope. We find over 500 new YSO candidates in seven massive star formation regions; these sources were selected using six colour-magnitude cuts. Via spectral energy distribution fitting to the data with YSO radiative transfer models we refine this list, identifying 105 high-confidence and 88 medium-confidence YSO candidates. For these sources, we constrain their evolutionary state and estimate their physical properties. The majority of our YSO candidates are massive protostars with an accreting envelope in the initial stages of formation. We fit the mass distribution of the Stage I YSOs with a Kroupa initial mass function and determine a global star formation rate of 0.039M_{sun}_/yr. This is higher than star formation rate estimates based on integrated UV fluxes. The new YSO candidates are preferentially located in clusters which correspond to seven active high-mass star-formation regions which are strongly correlated with the 8 and 24{mu}m emission from PAHs and warm dust. This analysis reveals an embedded high-mass star formation region, Spitzer I, which hosts the highest number of massive YSO candidates in NGC 6822. The properties of Spitzer I suggest it is younger and more active than the other prominent HII and star-formation regions in the galaxy.2019MNRAS.490..832Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/490/832CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/540/A135 : AGB population of NGC 6822 (Sibbons+, 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/490/832https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/490/832http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/490/832https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/490/832https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/490/832http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/490/832GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/490/832/table2 (Table of photometry for the high-confidence YSO Candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/490/832/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/490/832/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/490/832/table2?GETtext/xml+votable180.050000true296.0626-14.820.005555555555555556Cone search capability for table J/MNRAS/490/832/table3 (Table of photometry for the medium-confidence YSO Candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/490/832/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/490/832/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/490/832/table3?GETtext/xml+votable180.050000true296.0293-14.6860.005555555555555556Cone search capability for table J/MNRAS/490/832/table4 (Magnitudes and uncertainties for the possible YSO Candidates)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/490/832/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/490/832/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/490/832/table4?GETtext/xml+votable180.050000true296.043-14.8030.005555555555555556Cone search capability for table J/MNRAS/490/832/table7 (Physical Parameters of YSO Candidates fit with the Robitaille et al. (2006ApJS..167..256R) models)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/490/832/table7?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/490/832/table7?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/490/832/table7?GETtext/xml+votable180.050000true296.0626-14.820.005555555555555556Cone search capability for table J/MNRAS/490/832/table8 (Physical Parameters of YSO Candidates fit with the Robitaille (2017A&A...600A..11R) models)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/490/832/table8?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/490/832/table8?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/490/832/table8?GETtext/xml+votable180.050000true296.0626-14.820.0055555555555555566/29716 297186.772611666688002e-21 1.7798557115773645e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/490/832?format=asciiInfrareddefaultJ/MNRAS/490/832/table2Table of photometry for the high-confidence YSO CandidatesPAH[01] PAH flag (2)meta.codecharHmag? WFCAM H-band magnitudemagphot.mag;em.IR.Hfloatnullablee_Hmag? Error on Hmagmagstat.error;phot.magfloatnullableKmag? WFCAM K-band magnitudemagphot.mag;em.IR.Kfloatnullablee_Kmag? Error on Kmagmagstat.error;phot.magfloatnullable3.6magSpitzer/IRAC 3.6um band magnitudemagphot.mag;em.IR.3-4umfloate_3.6magError on 3.6magmagstat.errorfloat4.5magSpitzer/IRAC 4.5um band magnitudemagphot.mag;em.IR.4-8umfloate_4.5magError on 4.5magmagstat.errorfloat5.8magSpitzer/IRAC 5.8um band magnitudemagphot.flux.density;em.IR.4-8umfloate_5.8magError on 5.8magmagstat.errorfloat8.0magSpitzer/IRAC 8.0um band magnitudemagphot.flux.density;em.IR.8-15umfloate_8.0magError on 8.0magmagstat.errorfloat24magSpitzer/MIPS 24um band magnitudemagphot.flux.density;em.IR.15-30umfloate_24magError on 24magmagstat.errorfloatCMD[3-6] CMD score (1)meta.codeintPhotosph[01] Stellar Photosphere flag (3)meta.codecharCluster[-1/6] Cluster Membership flag (4)meta.code.memberintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[10/578] Source identifiermeta.id;meta.mainintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainJmag? WFCAM J-band magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag? Error on Jmagmagstat.error;phot.magfloatnullableJ/MNRAS/490/832/table3Table of photometry for the medium-confidence YSO CandidatesDEJ2000Declination (J2000)degpos.eq.dec;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[1/583] Source identifiermeta.id;meta.mainintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainJmag? WFCAM J-band magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag? Error on Jmagmagstat.error;phot.magfloatnullableHmag? WFCAM H-band magnitudemagphot.mag;em.IR.Hfloatnullablee_Hmag? Error on Hmagmagstat.error;phot.magfloatnullableKmag? WFCAM K-band magnitudemagphot.mag;em.IR.Kfloatnullablee_Kmag? Error on Kmagmagstat.error;phot.magfloatnullable3.6magSpitzer/IRAC 3.6um band magnitudemagphot.mag;em.IR.3-4umfloate_3.6magError on 3.6magmagstat.errorfloat4.5magSpitzer/IRAC 4.5um band magnitudemagphot.mag;em.IR.4-8umfloate_4.5magError on 4.5magmagstat.errorfloat5.8magSpitzer/IRAC 5.8um band magnitudemagphot.flux.density;em.IR.4-8umfloate_5.8magError on 5.8magmagstat.errorfloat8.0magSpitzer/IRAC 8.0um band magnitudemagphot.flux.density;em.IR.8-15umfloate_8.0magError on 8.0magmagstat.errorfloat24magSpitzer/MIPS 24um band magnitudemagphot.flux.density;em.IR.15-30umfloatPhotosph[01] Stellar Photosphere flag (3)meta.codecharCluster[-1/6] Cluster Membership flag (4)meta.code.memberinte_24magError on 24magmagstat.errorfloatCMD[3-6] CMD score (1)meta.codeintPAH[01] PAH flag (2)meta.codecharJ/MNRAS/490/832/table4Magnitudes and uncertainties for the possible YSO CandidatesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainJmag? WFCAM J-band magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag? Error on Jmagmagstat.error;phot.magfloatnullableHmag? WFCAM H-band magnitudemagphot.mag;em.IR.Hfloatnullablee_Hmag? Error on Hmagmagstat.error;phot.magfloatnullableKmag? WFCAM K-band magnitudemagphot.mag;em.IR.Kfloatnullablee_Kmag? Error on Kmagmagstat.error;phot.magfloatnullable3.6magSpitzer/IRAC 3.6um band magnitudemagphot.mag;em.IR.3-4umfloate_3.6magError on 3.6magmagstat.errorfloat4.5magSpitzer/IRAC 4.5um band magnitudemagphot.mag;em.IR.4-8umfloate_4.5magError on 4.5magmagstat.errorfloat5.8magSpitzer/IRAC 5.8um band magnitudemagphot.flux.density;em.IR.4-8umfloate_5.8mag? Error on 5.8magmagstat.errorfloatnullable8.0magSpitzer/IRAC 8.0um band magnitudemagphot.flux.density;em.IR.8-15umfloate_8.0mag? Error on 8.0magmagstat.errorfloatnullable24magSpitzer/MIPS 24um band magnitudemagphot.flux.density;em.IR.15-30umfloate_24mag? Error on 24magmagstat.errorfloatnullableCMD[0-6] CMD score (1)meta.codecharPAH[01] PAH flag (2)meta.codecharPhotosph[01] Stellar Photosphere flag (3)meta.codecharJ/MNRAS/490/832/table7Physical Parameters of YSO Candidates fit with the Robitaille et al. (2006ApJS..167..256R) modelsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[10/578] Source identifiermeta.id;meta.mainintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainchi2Chi-squared of the fitstat.fit.chi2;stat.fit.param;meta.modelledfloatnfitsNumber of well-fitting modelsmeta.numberintM*Best fit YSO candidate masssolMassphys.mass;meta.modelledinte_M*Error on M*solMassstat.errorintL*Best fit YSO candidate total luminositysolLumphys.luminosityinte_L*Error on L*solLumstat.errorintStage[1/3] Evolutionary stage (1)src.classintJ/MNRAS/490/832/table8Physical Parameters of YSO Candidates fit with the Robitaille (2017A&A...600A..11R) modelsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[10/578] Source identifiermeta.id;meta.mainintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainmodsetBest Robitaille (2017A&A...600A..11R) model setmeta.id;stat.fitcharnfitsNumber of best-fitting models from the most-likely model setmeta.numberintR*Best fit YSO candidate radiussolRadphys.size.radius;meta.modelledinte_R*Error on R*solRadstat.errorintTeffBest fit YSO candidate effective temperatureKphys.temperature.effective;meta.modelledinte_TeffError on TeffKstat.error;phys.temperature.effectiveintL*Best fit YSO candidate total luminositysolLumphys.luminosityinte_L*Error on L*solLumstat.errorint