J/AJ/157/112ivo://CDS.VizieR/J/AJ/157/112doi:10.26093/cds/vizier.51570112CDSPanwar N.Samal M.R.Pandey A.K.Singh H.P.Sharma S.2021-04-09T07:43:25Z2019-07-05T09:13:49ZCDS support team

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

cds-question@unistra.frh-ii-regionsyoung-stellar-objectsinfrared-photometryIt is well known that most of the stars form in rich clusters. However, recent Spitzer observations have shown that a significant number of stars also form in the distributed mode; their origin is not well understood. In this work, we aim to investigate clustered and distributed modes of star formation in the W4 complex. To do so, we identified and characterized the young stellar population associated with the region using homogeneous infrared data sets obtained from the Two Micron All Sky Survey, GLIMPSE, MIPS, and Wide-field Infrared Survey Explorer surveys. We make stellar surface density and minimum spanning tree maps to identify young clusters, and use Spitzer images to identify irradiated structures, such as elephant-trunk-like structures (ETLSs) and pillars in the region. The surface density distribution of the young stellar objects (YSOs) reveals three new clusterings and ~50% distributed protostars in the H II region. The clusters are of low-mass nature but significantly younger than the central cluster IC 1805. We identified ~38 ETLSs in the region, a majority of which consist of one or a few stars at their tips. We find that these stars are low-mass (<2 M_{sun}_) YSOs, located at the outskirts (>17 pc) of the cluster IC 1805 and are part of the scattered distributed population. We argued that the star formation in the ETLSs of W4 is going on possibly due to the triggering effect of the expanding W4 bubble. Although high-resolution photometric and spectroscopic data would be required to confirm the scenario, nonetheless, we discuss the implications of this scenario for our understanding of distributed low-mass star formation in cloud complexes as opposed to other mechanisms such as turbulent fragmentation and dynamical ejection.2019AJ....157..112Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/157/112CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)II/328 : AllWISE Data Release (Cutri+ 2013)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/157/112https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/157/112http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/157/112https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/157/112https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/157/112http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/157/112GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/157/112/table1 (YSOs from MIPS, IRAC/2MASS and WISE data)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/157/112/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/157/112/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/157/112/table1?GETtext/xml+votable180.050000true38.4218160.391770.0055555555555555565/826 6/3308 3310 36496.772611666688002e-21 1.7003137259100215e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/157/112?format=asciiInfrareddefaultJ/AJ/157/112/table1YSOs from MIPS, IRAC/2MASS and WISE dataSimbadNameSimbad column added by the CDSmeta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[1/524] Index identifiermeta.id;meta.mainintRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainJmag[8.13/17.2]? 2MASS J band magnitude (1)magphot.mag;em.IR.Jfloatnullablee_Jmag[0.02/0.22]? Uncertainty in Jmag (1)magstat.error;phot.magfloatnullableHmag[7.84/16.21]? 2MASS H band magnitude (1)magphot.mag;em.IR.Hfloatnullablee_Hmag[0.02/0.2]? Uncertainty in Hmag (1)magstat.error;phot.magfloatnullableKsmag[7.46/15.56]? 2MASS K_s_ band magnitude (1)magphot.mag;em.IR.Kfloatnullablee_Ksmag[0.01/0.22]? Uncertainty in Ksmag (1)magstat.error;phot.magfloatnullable3.6mag[6.73/16.54]? Spizter/IRAC 3.6 micron band magnitude (1)magphot.mag;em.IR.3-4umfloatnullablee_3.6mag[0.02/0.15]? Uncertainty in 3.6mag (1)magstat.errorfloatnullable4.5mag[5.92/15.84]? Spizter/IRAC 4.5 micron band magnitude (1)magphot.mag;em.IR.4-8umfloatnullablee_4.5mag[0.02/0.14]? Uncertainty in 4.5mag (1)magstat.errorfloatnullable24mag[0.72/9.53]? Spizter/MIPS 24 micron band magnitude (1)magphot.flux.density;em.IR.15-30umfloatnullablee_24mag[0.01/0.14]? Uncertainty in 24mag (1)magstat.errorfloatnullable3.4mag[6.72/16.81]? WISE 3.4 micron band magnitude (1)magphot.mag;em.IR.3-4umfloatnullablee_3.4mag[0.02/0.19]? Uncertainty in 3.4mag (1)magstat.errorfloatnullable4.6mag[6.36/15.79]? WISE 4.6 micron band magnitude (1)magphot.mag;em.IR.4-8umfloatnullablee_4.6mag[0.02/0.18]? Uncertainty in 4.6mag (1)magstat.errorfloatnullable12mag[3.08/11.38]? WISE 12 micron band magnitude (1)magphot.flux.density;em.IR.8-15umfloatnullablee_12mag[0.01/0.2]? Uncertainty in 12mag (1)magstat.errorfloatnullable