J/ApJ/787/107ivo://CDS.VizieR/J/ApJ/787/107doi:10.26093/cds/vizier.17870107CDSKuhn M.A.Feigelson E.D.Getman K.V.Baddeley A.J.Broos P.S.,Sills A.Bate M.R.Povich M.S.Luhman K.L.Busk H.A.Naylor T.,King R.R.2018-02-02T10:34:12Z2015-08-27T07:36:53ZCDS support team

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

cds-question@unistra.frstellar-associationsh-ii-regionsmolecular-cloudsinfrared-sourcesx-ray-sourcesThe clusters of young stars in massive star-forming regions show a wide range of sizes, morphologies, and numbers of stars. Their highly subclustered structures are revealed by the MYStIX project's sample of 31754 young stars in nearby sites of star formation (regions at distances <3.6kpc that contain at least one O-type star.) In 17 of the regions surveyed by MYStIX, we identify subclusters of young stars using finite mixture models --collections of isothermal ellipsoids that model individual subclusters. Maximum likelihood estimation is used to estimate the model parameters, and the Akaike Information Criterion is used to determine the number of subclusters. This procedure often successfully finds famous subclusters, such as the BN/KL complex behind the Orion Nebula Cluster and the KW-object complex in M17. A catalog of 142 subclusters is presented, with 1-20 subclusters per region. The subcluster core radius distribution for this sample is peaked at 0.17pc with a standard deviation of 0.43dex, and subcluster core radius is negatively correlated with gas/dust absorption of the stars --a possible age effect. Based on the morphological arrangements of subclusters, we identify four classes of spatial structure: long chains of subclusters, clumpy structures, isolated clusters with a core-halo structure, and isolated clusters well fit by a single isothermal ellipsoid.2014ApJ...787..107Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/787/107CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/802/60 : Structure or young stellar clusters. II. (Kuhn+, 2015)J/ApJS/213/1 : The MSFRs Omnibus X-ray Catalog (MOXC) (Townsley+, 2014)J/ApJS/209/32 : Probable young stars in the MYStIX project (Broos+, 2013)J/ApJS/209/31 : The MYStIX IR-Excess Source catalog (MIRES) (Povich+, 2013)J/ApJS/209/30 : MYStIX project: Bayesian matching (Naylor+, 2013)J/ApJS/209/29 : MYStIX: Mid-IR observations and catalogs (Kuhn+, 2013)J/ApJS/209/28 : MYStIX Wide-Field NIR data: crowded fields (King+, 2013)J/ApJS/209/27 : MYStIX: the Chandra X-ray sources (Kuhn+, 2013)J/AJ/144/192 : Spitzer survey of Orion A & B. I. YSO catalog (Megeath+, 2012)J/MNRAS/426/2917 : X-rays sources in Trumpler 37 (Getman+, 2012)J/ApJS/194/14 : A Pan-Carina YSO catalog (Povich+, 2011)J/ApJS/194/11 : Chandra study of Trumpler 15 in Carina (Wang+, 2011)J/ApJS/194/9 : X-ray star clusters in the Carina complex (Feigelson+, 2011)J/ApJS/194/2 : Chandra Carina Complex Project (CCCP) catalog (Broos+, 2011)J/ApJ/725/2485 : X-rays from the star-forming complex W40 (Kuhn+, 2010)J/ApJ/708/1760 : Flux estimations of faint X-ray sources (Getman+, 2010)J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)J/ApJ/699/1454 : YSOs around Cepheus B (Getman+, 2009)J/AJ/138/227 : Stellar clusters in NGC 6334 complex (Feigelson+, 2009)J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)J/ApJ/676/1109 : Velocities of stars in ONC (Furesz+, 2008)J/ApJ/675/464 : Chandra observations of NGC 2244 (Wang+, 2008)J/A+A/476/199 : Trumpler 14 JHKL' photometry (Ascenso+, 2007)J/A+A/468/353 : XMM-Newton Extended Survey of Taurus (Guedel+, 2007)J/ApJ/641/389 : Millimetric observations of IRDC cores (Rathborne+, 2006)J/ApJS/160/319 : COUP: observations and source lists (Getman+, 2005)J/AJ/128/1254 : VLT 3.8{mu}m Trapezium catalog (Lada+, 2004)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/787/107https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/787/107http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/787/107https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/787/107https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/787/107http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/787/107GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/787/107/table3 (Membership of MYStIX subclusters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/787/107/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/787/107/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/787/107/table3?GETtext/xml+votable180.050000true83.6227264-5.39373020.005555555555555556Cone search capability for table J/ApJ/787/107/table1 (*MYStIX targets for subcluster analysis)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/787/107/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/787/107/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/787/107/table1?GETtext/xml+votable180.050000true83.8221-5.39110.005555555555555556Cone search capability for table J/ApJ/787/107/table2 (MYStIX subcluster properties)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/787/107/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/787/107/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/787/107/table2?GETtext/xml+votable180.050000true83.810833-5.3752780.0055555555555555565/10614 10615 6/1285 1287 1296 1298 14682 14704 21438 21439 22243 22249 22804 22805 22855 23637 23639 28890 28891 28913 28915 29116 29118 29461 29463 29504 29506 30341 30352 37333 37872 37884 38016 39907https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/787/107?format=asciiInfraredX-raydefaultJ/ApJ/787/107/table3Membership of MYStIX subclustersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMCPMMYStIX source name (HHMMSS.ss+DDMMSS.s; J2000) (1)meta.id;meta.maincharindexedB13Details from Broos et al. 2013, J/ApJS/209/32meta.ref.urlcharRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainindexedDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainindexedX[0/1] X-ray selection? (2)meta.codeintIR[0/1] IR-excess selected? (2)meta.codeintOB[0/1] OB star? (2)meta.codeintME[0.5/7.6]? Median 0.5-8.0keV band X-ray energykeVphys.energy;stat.medianfloatnullableJ-H[-2.1/7.5]? J-H color indexmagphot.color;em.IR.J;em.IR.HfloatnullableLXtc[27.4/33.6]? The 0.5-8.0kev band X-ray luminosity (erg/s)log(1e-07W)phys.luminosity;em.X-rayfloatnullableMSFRMYStIX region namemeta.id;obs.fieldcharm_MSFRSubcluster assignment (G1)meta.code.multipcharJ/ApJ/787/107/table1*MYStIX targets for subcluster analysisrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegMassive star-forming region (MSFR) namemeta.id;meta.maincharDist[0.4/3.6] Distance to region used in MYStIX analysis (Feigelson et al. 2013ApJS..209...26F)kpcpos.distance;pos.heliocentricfloatlogFX[-6.8/-5.9] Apparent 0.5-8.0keV X-ray photon flux limit imposed for spatial uniformityph.s**-1.cm**-2phot.flux;em.X-rayfloatNs[246/2790] Total number of stars used in analysismeta.numberintNsp[38/96] Percentage of all MPCMs%meta.numberintNx[174/2043] Number of X-ray starsmeta.numberintNir[49/815] Number of MYStIX InfraRed Excess (MIRES) starsmeta.numberintNob[1/134] Number of OB starsmeta.numberintMSFRMYStIX region name as in tables 2 and 3; column added by CDSmeta.idcharprimaryNcNumber of subcluster(s) in this regionmeta.numberintnullableSimbadSimbad column added by the CDSmeta.ref.urlchar_RAPositions from SIMBAD (right ascension part)degpos.eq.ra;meta.main_DEPositions from SIMBAD (declination part)degpos.eq.dec;meta.mainJ/ApJ/787/107/table2MYStIX subcluster propertiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMSFRMYStIX region namemeta.id;obs.fieldcharm_MSFRSubcluster assignment (G1)meta.code.multipcharRAJ2000Hour of right ascension (J2000) (1)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000) (1)pos.eq.dec;meta.mainamaj[0.01/10.2] Semimajor axis of the ellipsoid core regionpcphys.sizefloatbmin[0.01/2.1] Semiminor axis of the ellipsoid core regionpcphys.sizefloatell[0/0.9] Ellipticitysrc.ellipticityfloatPA[0/248] Orientation angle of the ellipse; east from northdegpos.posAngintNs[2/834] Number of stars (2)meta.numberintJ-H[0.6/3] J-H color index as measure of absorptionmagphot.color;em.IR.J;em.IR.HfloatEmed[1/4.4] Median X-ray median energy as a measure of absorptionkeVphys.absorption;em.X-ray;stat.medianfloatNmNumber of members in this subclustermeta.numberintnullablePapIIDisplay data from Paper II (Kuhn+, 2015, J/ApJ/802/60) for this subclustermeta.ref.urlchar