J/ApJS/184/18ivo://CDS.VizieR/J/ApJS/184/18doi:10.26093/cds/vizier.21840018CDSGutermuth R.A.Megeath S.T.Myers P.C.Allen L.E.Pipher J.L.,Fazio G.G.2017-10-09T13:34:50Z2010-03-22T08:19:45ZCDS support team

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

cds-question@unistra.fryoung-stellar-objectsinfrared-photometrystellar-associationssurveysWe present a uniform mid-infrared imaging and photometric survey of 36 young, nearby, star-forming clusters and groups using Spitzer IRAC and MIPS. We have confidently identified and classified 2548 young stellar objects (YSOs) using recently established mid-infrared color-based methods. We have devised and applied a new algorithm for the isolation of local surface density enhancements from point source distributions, enabling us to extract the overdense cores of the observed star-forming regions for further analysis. We have compiled several basic structural measurements of these cluster cores from the data, such as mean surface densities of sources, cluster core radii, and aspect ratios, in order to characterize the ranges for these quantities. We find that a typical cluster core is 0.39pc in radius, has 26 members with infrared excess in a ratio of Class II to Class I sources of 3.7, is embedded in a A_Ks_=0.8mag cloud clump, and has a surface density of 60pc^-2^. We examine the nearest neighbor distances among the YSOs in several ways, demonstrating similarity in the spacings between Class II and Class I sources but large member clusters appear more dense than smaller clusters. We demonstrate that near-uniform source spacings in cluster cores are common, suggesting that simple Jeans fragmentation of parsec-scale cloud clumps may be the dominant process governing star formation in nearby clusters and groups. Finally, we compare our results to other similar surveys in the literature and discuss potential biases in the data to guide further interpretation.2009ApJS..184...18Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/184/18CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/111/1964 : JHK photometry of NGC1333 (Lada+, 1996)J/AJ/121/974 : JHK photometry in Cha I (Gomez+, 2001)J/ApJ/575/354 : Young stellar objects in the NGC 1333 (Getman+, 2002)J/AJ/126/1916 : JHK photometry of young clusters near the Sun (Porras+, 2003)J/other/ChA+A/28.308 : JHK' photometry in GGD 12-15 region (Fang+, 2004)J/AJ/131/1574 : Infrared photometry of IC348 members (Lada+, 2006)J/ApJ/649/862 : IR phot. of IC 348 pre-main-sequence stars (Cieza+, 2006)J/ApJ/663/1149 : Spitzer survey of Serpens YSO population (Harvey+, 2007)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/184/18https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/184/18http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/184/18https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/184/18https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/184/18http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/184/18GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/184/18/table4 (Spitzer-identified YSOs: IRAC, MIPS, and 2MASS magnitudes)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/184/18/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/184/18/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/184/18/table4?GETtext/xml+votable180.050000true1.066916768.45736110.005555555555555556Spitzer6/859 862 1159 1168 1169 1170 1231 1539 1590 1591 3198 3759 13050 14029 14031 14040 14042 14621 14623 14696 15409 15412 15476 15667 15670 15671 15673 15676 15681 15682 15684 15759 15781 21447 21456 21457 21458 23549 23646 24158 24189 24191 24360 30251 30366 30388 36957 37128 42611 42614 42970 42971 42981 42992 42993 47742 47825 478286.772611666688002e-21 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/184/18?format=asciiInfrareddefaultJ/ApJS/184/18/table2Spitzer young cluster survey observations tableSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterCluster namemeta.id.parentprimaryAORAstronomical Observation Request identification numbermeta.idintDateObservation datetime.epochnullableSSCBCDSSC BCD calibration pipeline version used to reduce each regionmeta.softwarecharJ/ApJS/184/18/table4Spitzer-identified YSOs: IRAC, MIPS, and 2MASS magnitudesSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintClusterCluster namemeta.id.parentSeqRunning index number within clustermeta.id;meta.mainintRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainJmag? 2MASS J band magnitudemagphot.mag;em.IR.Jfloatnullablee_Jmag? Uncertainty in Jmagmagstat.error;phot.mag;em.IR.JfloatnullableHmag? 2MASS H band magnitudemagphot.mag;em.IR.Hfloatnullablee_Hmag? Uncertainty in Hmagmagstat.error;phot.mag;em.IR.HfloatnullableKsmag? 2MASS K_S_ band magnitudemagphot.mag;em.IR.Kfloatnullablee_Ksmag? Uncertainty in Ksmagmagstat.error;phot.mag;em.IR.Kfloatnullable3.6mag? Spitzer/IRAC 3.6um band magnitudemagphot.mag;em.IR.3-4umfloatnullablee_3.6mag? Uncertainty in 3.6magmagstat.errorfloatnullable4.5mag? Spitzer/IRAC 4.5um band magnitudemagphot.mag;em.IR.4-8umfloatnullablee_4.5mag? Uncertainty in 4.5magmagstat.errorfloatnullable5.8mag? Spitzer/IRAC 5.8um band magnitudemagphot.flux.density;em.IR.4-8umfloatnullablee_5.8mag? Uncertainty in 5.8magmagstat.errorfloatnullable8.0mag? Spitzer/IRAC 8.0um band magnitudemagphot.flux.density;em.IR.8-15umfloatnullablee_8.0mag? Uncertainty in 8.0magmagstat.errorfloatnullable24mag? Spitzer/MIPS 24um band magnitudemagphot.flux.density;em.IR.15-30umfloatnullablee_24mag? Uncertainty in 24magmagstat.errorfloatnullableAKs? The K_S_ band extinction (1)magphys.absorptionfloatnullablealpha? Mid-infrared spectral energy index (2)spect.indexfloatnullableClSource classification (3)src.classchar2MDisplay the 2MASS data (Cutri et al. 2003, Cat. II/246)meta.ref.urlchar