J/MNRAS/477/298ivo://CDS.VizieR/J/MNRAS/477/298doi:10.26093/cds/vizier.74770298CDSGetman K.V.Kuhn M.A.Feigelson E.D.Broos P.S.Bate M.R.Garmire G.P.2024-08-18T20:19:10Z2021-06-25T15:55:52ZCDS support team

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

cds-question@unistra.frmolecular-cloudsopen-star-clusterspre-main-sequence-starsgalaxy-classification-systemsThe SFiNCs (Star Formation in Nearby Clouds) project is an X-ray/infrared study of the young stellar populations in 22 star-forming regions with distances <~1kpc designed to extend our earlier MYStIX (Massive Young Star-Forming Complex Study in Infrared and X-ray) survey of more distant clusters. Our central goal is to give empirical constraints on cluster formation mechanisms. Using parametric mixture models applied homogeneously to the catalogue of SFiNCs young stars, we identify 52 SFiNCs clusters and 19 unclustered stellar structures. The procedure gives cluster properties including location, population, morphology, association with molecular clouds, absorption, age (Age_JX_), and infrared spectral energy distribution (SED) slope. Absorption, SED slope, and Age_JX_ are age indicators. SFiNCs clusters are examined individually, and collectively with MYStIX clusters, to give the following results. (1) SFiNCs is dominated by smaller, younger, and more heavily obscured clusters than MYStIX. (2) SFiNCs cloud-associated clusters have the high ellipticities aligned with their host molecular filaments indicating morphology inherited from their parental clouds. (3) The effect of cluster expansion is evident from the radius-age, radius-absorption, and radius-SED correlations. Core radii increase dramatically from ~0.08 to ~0.9pc over the age range 1-3.5Myr. Inferred gas removal time-scales are longer than 1Myr. (4) Rich, spatially distributed stellar populations are present in SFiNCs clouds representing early generations of star formation. An appendix compares the performance of the mixture models and non-parametric minimum spanning tree to identify clusters. This work is a foundation for future SFiNCs/MYStIX studies including disc longevity, age gradients, and dynamical modelling.2018MNRAS.477..298Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/477/298CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJS/229/28 : SFiNCs: X-ray, IR and membership catalogs (Getman+, 2017)J/ApJ/787/109 : Age estimates for NGC 2024 and ONC stars (Getman+, 2014)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/477/298https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/477/298http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/477/298https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/477/298https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/477/298http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/477/298GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/477/298/table1 (SFiNCs targets for cluster analysis)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/477/298/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/477/298/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/477/298/table1?GETtext/xml+votable180.050000true0.558333367.41666670.005555555555555556Cone search capability for table J/MNRAS/477/298/table2 (*SFiNCs clusters from mixture model)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/477/298/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/477/298/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/477/298/table2?GETtext/xml+votable180.050000true0.5087130667.520258890.005555555555555556Cone search capability for table J/MNRAS/477/298/table4 (Membership of SFiNCs clusters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/477/298/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/477/298/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/477/298/table4?GETtext/xml+votable180.050000true0.1411567.412846110.0055555555555555566/859 862 1231 1538-1539 3755 3758-3759 13050-13051 14029 14031 14040 14042 14621 14623 15662-15663 15681-15684 15686 15688-15689 15748-15749 16197 21438-21439 21447 21456 21458-21459 22804-22805 22867 22873 22876 22878 30341 30343 30366 424411.1166583743361574e-19 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/477/298?format=asciiOpticaldefaultJ/MNRAS/477/298/table1SFiNCs targets for cluster analysisSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegionSFiNCs SFR (SFiNCs regions) (1)obs.fieldcharDistanceDistance to SFR (SFiNCs regions) (1)kpcpos.distancefloatSPCMsTotal number of SPCMs (SFiNCs regions) (1)meta.numberintlogFXlimApparent (0.5-8)keV X-ray photon flux limit imposed for spatial uniformity (SPCM subsample for cluster identification)ph.s**-1.cm**-2phot.flux;em.X-rayfloatN*Total number of SPCMs used for the cluster analysis (SPCM subsample for cluster identification)meta.numberintX-rayNumber of X-ray selected SPCMs that lie within the Chandra ACIS-I field and have their X-ray photometric flux above the FX,lim value (SPCM subsample for cluster identification)meta.numberintIRENumber of non-X-ray disc-bearing SPCMs that lie within the Chandra ACIS-I field (SPCM subsample for cluster identification)meta.numberintOBNumber of OB-type stars within the SPCM subsample used for the cluster identification analysis (SPCM subsample for cluster identification)meta.numberint_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/MNRAS/477/298/table2*SFiNCs clusters from mixture modelu_DEJ2000Uncertainty flag on DEdegmeta.code.error;pos.eq.deccharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterCluster component name, labelled from west to eastmeta.id;meta.maincharRAJ2000Ellipsoide centre right ascension (J2000)degpos.eq.ra;meta.mainu_RAJ2000Uncertainty flag RAdegmeta.code.error;pos.eq.racharDEJ2000Ellipsoide centre declination (J2000)degpos.eq.dec;meta.maine_Pos? Position error as 68 per cent error circlearcsecstat.errorintnullableRcCore radius as an average between the semimajor and semiminor axes of the ellipsoid componentpcphys.size.radius;stat.meanfloatu_RcUncertainty flag on Rcmeta.code.errorchare_Rc/Rc? Core radius fractional statistical error (68 per cent confidence interval)stat.errorfloatnullableepsEllipticitysrc.ellipticityfloatu_epsUncertainty flag on epsmeta.code.errorchare_eps/eps? Ellipticity fractional statistical errorstat.errorfloatnullablephiOrientation angle of the ellipse (east from north)degpos.posAngintu_phiUncertainty flag on phimeta.code.errorcharNNumber of stars estimated by integrating the model component out to four times the size of the coremeta.numberintu_NUncertainty flag on Nmeta.code.errorchare_N/N? Number of stars fractional statistical errorstat.error;phys.abundfloatnullableCloud[CR-] Relation to molecular clouds (1)meta.codecharJ/MNRAS/477/298/table3Mixture model goodness of fit.recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegionStar-forming regionmeta.idcharNsubcltNumber of clusters in the modelmeta.numberintchi2Pearson's chi^2^ value (1)stat.fit.chi2;stat.valuefloatdofDegrees of freedomstat.fit.dofintPchi2Two-sided p-value for the null hypothesis that the observed YSO distribution is drawn from the model (2)stat.fit.goodnessfloatJ/MNRAS/477/298/table4Membership of SFiNCs clustersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegionSFiNCs SFR nameobs.fieldcharDesigSource IAU designation (HHMMSS.s+DDMMSS.s)meta.id;meta.maincharRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainFlagThree-digit flag (1)meta.code.errorintME? X-ray median energy in the (0.5-8)keV bandkeVphys.energy;stat.medianfloatnullableJmag? 2MASS J magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag? 2MASS J magnitude errormagstat.error;phot.magfloatnullableHmag? 2MASS H magnitudemagphot.mag;em.IR.Hfloatnullablee_Hmag? 2MASS H magnitude errormagstat.error;phot.magfloatnullablealphaIRAC? Apparent SED slope (2)meta.crypticfloatnullablee_alphaIRAC? Apparent SED slope errorstat.errorfloatnullablelogLXtc? Intrinsic X-ray luminosity in the (0.5-8)keV bandlog(1e-07W)phys.luminosity;em.X-rayfloatnullableAgeJX? Stellar age estimate using the method of Getman et al. (2014, Cat. J/ApJ/787/109)Myrtime.agefloatnullableClusCluster assignment (3)meta.codecharJ/MNRAS/477/298/table5Properties of SFiNCs clustersAgeJX? Medium ageMyrtime.agefloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterCluster component name (1)meta.id;meta.maincharN4dataNumber of observed SPCMsmeta.numberintNJH? Number of observed SPCMs with available reliable J-H colour (2)meta.numberintnullableJ-H? J-H colourmagphot.color;em.IR.J;em.IR.Hfloatnullablee_J-H? J-H colour error (3)magstat.error;phot.color;em.IR.JfloatnullableNME? Number of observed SPCMs with available X-ray median energy ME (2)meta.numberintnullableME? X-ray median energy in the (0.5-8)keV bandkeVphys.energy;stat.medianfloatnullablee_ME? X-ray median energy error (3)keVstat.errorfloatnullableNIRAC? Number of observed SPCMs with available IRAC SED slope (alphaIRAC) (2)meta.numberintnullablealphaIRAC? Median SED slopemeta.crypticfloatnullablee_alphaIRAC? Median SED slope error (3)stat.errorfloatnullableNAgeJX? Number of observed SPCMs with available age estimates (AgeJX) (2)meta.numberintnullablee_AgeJX? Medium age error (3)Myrstat.errorfloatnullableJ/MNRAS/477/298/table6Properties of MYStIX clustersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterMYStIX cluster component namemeta.id;meta.maincharN4modelNumber of observed stars estimated by integrating the model component out to four times the size of the coremeta.numberintlog(Rc)logarithm of cluster core radiuslog(pc)phys.size.radiusfloatepsCluster ellipticitysrc.ellipticityfloatJ-HMedian J-H colourmagphot.color;em.IR.J;em.IR.HfloatMEX-ray median energy in the (0.5-8)keV bandkeVphys.energy;stat.medianfloatlog(AgeJX)? log Agelog(yr)time.agefloatnullablealphaIRAC? SED slopemeta.crypticfloatnullableCloudRelation to molecular clouds (1)meta.codecharJ/MNRAS/477/298/tablea1Clusters in common between SFiNCs and Gutermuth et al. (2009, Cat. J/ApJS/184/18, G09)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSFRStar-forming regionmeta.id;meta.maincharm_SFRSFiNCs cluster component namemeta.code.multipcharSizeCluster size (1)pcphys.angSizefloatNumberObserved number of YSOsmeta.numberintSIGMAmeanMean stellar density derived from SFiNCs model (2)pc**-2src.densityintNameCluster name from G09meta.idcharRhullCluster radius from G09 (3)pcphys.size.radiusfloatsigmameanMean stellar density inferred from the analysis of G09 (3)pc**-2src.densityint