J/A+A/646/A103ivo://CDS.VizieR/J/A+A/646/A103doi:10.26093/cds/vizier.36460103CDSDuronea N.U.Cichowolski S.Bronfman L.Mendoza E.Finger R.,Suad L.A.Corti M.Reynoso E.M.2021-07-05T11:54:42Z2021-05-05T07:43:17ZCDS support team

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

cds-question@unistra.frinterstellar-mediumyoung-stellar-objectsinfrared-photometryWith the aim of studying the physical properties of Galactic IR bubbles and to explore their impact in massive star formation, we present a study of the IR bubble S169, associated with the massive star forming region IRAS 12326-6245. We used CO (2-1),^13^CO (2-1), C^18^O (2-1), HCN (3-2), and HCO^+^ (3-2) line data obtained with the APEX telescope using the on-the-fly full sampling technique to study the properties of the molecular gas in the nebula and the IRAS source. To analyze the properties and distribution of the dust, we made use of images obtained from the IRAC-GLIMPSE, Herschel, and ATLASGAL archives. The properties of the ionized gas in the nebula were studied using radio continuum and H{alpha} images obtained from the SUMSS survey and SuperCOSMOS database, respectively. In our search for stellar and protostellar objects in the region, we used point source calalogs obtained from the MSX, WISE, GLIMPSE, 2MASS, AAVSO, ASCC-2.5V3, and GAIA databases. The new APEX observations allowed us to identify three molecular components, each one associated with different regions of the nebula, namely: at -39km/s (component A), -25km/s (component B), and -17km/s (component C). Component A is shown to be the most dense and clumpy. Six molecular condensations (MC1 to MC6) were identified in this component, with MC3 (the densest and more massive one) being the molecular counterpart of IRAS 12326-6245. For this source, we estimated an H_2_ column density up to 8x10^23^cm^-2^. An LTE analysis of the high density tracer lines HCO^+^ (3-2) and HCN (3-2) on this source, assuming 50 and 150K, respectively, indicates column densities of N(HCO^+^)=(5.2+/-0.1)x10^13^cm^-2^ and N(HCN)=(1.9+/-0.5)x10^14^cm^-2^. To explain the morphology and velocity of components A, B, and C, we propose a simple model consisting of a partially complete semisphere-like structure expanding at ~12km/s. The introduction of this model has led to a discussion about the distance to both S169 and IRAS 12326-6245, which was estimated to be ~2kpc. Several candidate YSOs were identified, projected mostly onto the molecular condensations MC3, MC4, and MC5, which indicates that the star-formation process is very active at the borders of the nebula. A comparison between observable and modeled parameters was not enough to discern whether the collect-and-collapse mechanism is acting at the edge of S169. However, other processes such as radiative-driven implosion or even a combination of both mechanisms, namely, collect-and-collapse and radiative-driven implosion, could be acting simultaneously in the region.2021A&A...646A.103Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/646/A103CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toV/114 : MSX6C Infrared Point Source Catalog (Egan+ 2003)II/311 : WISE All-Sky Data Release (Cutri+ 2012)II/293 : GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/646/A103https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/646/A103http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/646/A103https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/646/A103https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/646/A103http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/646/A103GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/646/A103/tablea1m (YSO candidates obtained from MSX catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/646/A103/tablea1m?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/646/A103/tablea1m?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/646/A103/tablea1m?GETtext/xml+votable180.050000true188.896667-63.0416670.005555555555555556Cone search capability for table J/A+A/646/A103/tablea1w (YSO candidates obtained from WISE catalogs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/646/A103/tablea1w?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/646/A103/tablea1w?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/646/A103/tablea1w?GETtext/xml+votable180.050000true188.88125-63.0517780.005555555555555556Cone search capability for table J/A+A/646/A103/tablea1s (YSO candidates obtained from Spitzer catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/646/A103/tablea1s?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/646/A103/tablea1s?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/646/A103/tablea1s?GETtext/xml+votable180.050000true188.909583-62.9059720.0055555555555555566/43013 430158.157980699529898e-21 6.513807192489934e-20https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/646/A103?format=asciiInfrareddefaultJ/A+A/646/A103/tablea1mYSO candidates obtained from MSX catalogrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintOrigin[MSX ] Source originmeta.codecharSeq[1/2] Sequential numbermeta.recordintNameSource name, GLLL.llll+BB.bbbb, MSX6C GLLL.llll+BB.bbbb in Simbadmeta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainF8MSX6C 8.28um flux densityJyphot.flux.density;em.IR.8-15umfloatF12MSX6C 12.13um flux densityJyphot.flux.density;em.IR.8-15umfloatF14MSX6C 14.65um flux densityJyphot.flux.density;em.IR.8-15umfloatF21MSX6C 21.34um flux densityJyphot.flux.density;em.IR.15-30umfloatNoteNotes (class, match with other YSO and with ^13^CO/CO or IR structure)meta.notecharJ/A+A/646/A103/tablea1wYSO candidates obtained from WISE catalogsSeq[3/50] Sequential numbermeta.recordintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintOrigin[WISE ] Source originmeta.codecharNameSource name, JHHMMSS.ss+DDMMSS.s, WISE JHHMMSS.ss+DDMMSS.smeta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainW1WISE W1 magnitudemagphot.mag;em.IR.3-4umfloatW2WISE W2 magnitudemagphot.mag;em.IR.4-8umfloatW3WISE W3 magnitudemagphot.flux.density;em.IR.8-15umfloatW4WISE W4 magnitudemagphot.flux.density;em.IR.15-30umfloatNoteNotes (class, match with other YSO and with ^13^CO/CO or IR structure)meta.notecharJ/A+A/646/A103/tablea1sYSO candidates obtained from Spitzer catalogDEJ2000Declination (J2000)pos.eq.dec;meta.mainrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintOrigin[Spitzer] Source originmeta.codecharSeq[51/74] Sequential numbermeta.recordintNameSource name, GLLL.llll+BB.bbbb, GLIMPSE GLLL.llll+BB.bbbbmeta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.main[3.6]Spitzer/IRAC 3.6um magnitudemagphot.mag;em.IR.3-4umfloat[4.5]Spitzer/IRAC 4.5um magnitudemagphot.mag;em.IR.4-8umfloat[5.8]Spitzer/IRAC 5.8um magnitudemagphot.flux.density;em.IR.4-8umfloat[8.0]Spitzer/IRAC 8.0um magnitudemagphot.flux.density;em.IR.8-15umfloatNoteNotes (class, match with other YSO and with ^13^CO/CO or IR structure)meta.notechar