J/ApJ/682/445ivo://CDS.VizieR/J/ApJ/682/445doi:10.26093/cds/vizier.16820445CDSChavarria L.A.Allen L.E.Hora J.L.Brunt C.M.Fazio G.G.2017-09-27T05:55:37Z2010-12-16T15:28:44ZCDS support team

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

cds-question@unistra.frh-ii-regionsinfrared-photometryyoung-stellar-objectsWe present Spitzer IRAC, NOAO 2.1m Flamingos, Keck NIRC, and FCRAO SEQUOIA observations of the massive star-forming complex S254-S258, covering an area of 25'x20'. Using a combination of the IRAC and NIR data, we identify and classify the young stellar objects (YSOs) in the complex. We detect 510 sources with near- or mid-IR excess, and we classify 87 Class I and 165 Class II sources. The YSOs are found in clusters surrounded by isolated YSOs in a low-density distributed population. The ratio of clustered to total YSOs is 0.8. We identify six new clusters in the complex. One of them, G192.63-00, is located around the ionizing star of the HII region S255. We hypothesize that the ionizing star of S255 was formed in this cluster. We also detect a southern component of the cluster in HII region S256. The cluster G192.54-0.15, located inside HII region S254 has a V_LSR_ of 17km/s with respect to the main cloud, and we conclude that it is located in the background of the complex. The structure of the molecular cloud is examined using ^12^CO, and ^13^CO, as well as a near-IR extinction map. The main body of the molecular cloud has V_LSR_ between 5 and 9km/s. The arc-shaped structure of the molecular cloud following the border of the HII regions and the high column density in the border of the HII regions support the idea that the material has been swept up by the expansion of the HII regions.2008ApJ...682..445Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/682/445CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJ/643/965 : Spitzer photometry of the Trifid nebula (M20) (Rho+, 2006)J/ApJ/642/972 : IR photometry of a star-forming core in NGC 2264 (Young+,J/ApJS/177/551 : Spitzer c2d survey of Lupus dark clouds (Merin+, 2008)J/ApJ/675/1375 : IRAC/MIPS photometry in Cha I (Luhman+, 2008)J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)J/A+A/503/107 : Spitzer/IRAC view of Sh2-284 (Puga+, 2009)J/BaltA/19/1 : YSOs in Camelopardalis (Straizys+, 2010)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/682/445https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/682/445http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/682/445https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/682/445https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/682/445http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/682/445GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/682/445/table2 (JHK and Spitzer photometry of sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/682/445/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/682/445/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/682/445/table2?GETtext/xml+votable180.050000true92.9794217.950620.005555555555555556Cone search capability for table J/ApJ/682/445/table4 (*Parameters of clusters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/682/445/table4?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/682/445/table4?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/682/445/table4?GETtext/xml+votable180.050000true93.22517.986110.005555555555555556Spitzer6/23968 239692.0616683193919197e-20 1.7134409597567747e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/682/445?format=asciiInfrareddefaultJ/ApJ/682/445/table2JHK and Spitzer photometry of sourcesHmag? KPNO/FLAMINGOS H band magnitude (1.65um)magphot.mag;em.IR.Hfloatnullablee_Hmag? Error in Hmagmagstat.error;phot.mag;em.IR.Hfloatnullable5.8um? Spitzer/IRAC 5.8 micron band magnitudemagphot.flux.density;em.IR.4-8umfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainindexedDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainindexedJmag? KPNO/FLAMINGOS J band magnitude (1.24um)magphot.mag;em.IR.Jfloatnullablee_Jmag? Error in Jmagmagstat.error;phot.mag;em.IR.JfloatnullableKmag? KPNO/FLAMINGOS K band magnitude (2.21um)magphot.mag;em.IR.Kfloatnullablee_Kmag? Error in Kmagmagstat.error;phot.mag;em.IR.Kfloatnullable3.6um? Spitzer/IRAC 3.6 micron band magnitudemagphot.mag;em.IR.3-4umfloatnullablee_3.6um? Error in 3.6ummagstat.errorfloatnullable4.5um? Spitzer/IRAC 4.5 micron band magnitudemagphot.mag;em.IR.4-8umfloatnullablee_4.5um? Error in 4.5ummagstat.errorfloatnullablee_5.8um? Error in 5.8ummagstat.errorfloatnullable8.0um? Spitzer/IRAC 8.0 micron band magnitudemagphot.flux.density;em.IR.8-15umfloatnullablee_8.0um? Error in 8.0ummagstat.errorfloatnullablealpha? Observed IRAC SED slope ({alpha}_IRAC_) (1)spect.indexfloatnullableSimbadSimbad column added by the CDSmeta.refcharJ/ApJ/682/445/table4*Parameters of clustersSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCluster name(s)meta.id;meta.maincharRAJ2000Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of declination (J2000)pos.eq.dec;meta.mainIRNumber of stars with IR-excess, including Class I and Class II.meta.numberintNCorrected number of cluster members, see section 4.2meta.numberintINumber of Class I sourcesmeta.numberintIINumber of Class II sourcesmeta.numberintI/II? Ratio of Class II to Class I sourcesmeta.numberfloatnullablef_I/II[g] missed sources (1)meta.codecharI/IRRatio of Class I to IR-excess sourcesmeta.numberfloatsigsMean surface density of starspc**-2src.densityintsigsMPeak surface density of starspc**-2src.densityintsiggMean ^13^CO surface densitycm**-2src.densitydoublesiggMPeak ^13^CO surface densitycm**-2src.densitydoubleMgasMass of gas in the clustersolMassphys.massintepsStar formation efficiency (2)stat.paramfloat