J/MNRAS/435/2003ivo://CDS.VizieR/J/MNRAS/435/2003doi:10.26093/cds/vizier.74352003CDSHindson L.Thompson M.A.Urquhart J.S.Faimali A.Johnston-Hollitt M.,Clark J.S.Davies B.2024-08-06T20:17:00Z2014-11-07T13:11:59ZCDS support team

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

cds-question@unistra.frh-ii-regionsgalaxy-classification-systemsradio-astronomyWe present 109-115GHz (3mm) wide-field spectral line observations of ^12^CO, ^13^CO and C^18^O J=1-0 molecular emission and 5.5 and 8.8GHz (6 and 3cm) radio continuum emission towards the high-mass star-forming complex known as G305. The morphology of G305 is dominated by a large evacuated cavity at the centre of the complex driven by clusters of O stars surrounded by molecular gas. Our goals are to determine the physical properties of the molecular environment and reveal the relationship between the molecular and ionized gas and star formation in G305. This is in an effort to characterize the star-forming environment and constrain the star formation history in an attempt to evaluate the impact of high-mass stars on the evolution of the G305 complex. Analysis of CO emission in G305 reveals 156 molecular clumps with the following physical characteristics; excitation temperatures ranging from 7 to 25K, optical depths of 0.2-0.9, H_2_) column densities of 0.1-4.0x10^22^cm^-2^, clump masses ranging from 10^2^ to 10^4^M_{sun}_ and a total molecular mass of >3.5x10^5^M_{sun}_. The 5.5 and 8.8GHz radio continuum emission reveals an extended low surface brightness ionized environment within which we identify 15 large-scale features with a further eight smaller sources projected within these features. By comparing to mid-infrared emission and archival data, we identify nine HII regions, seven compact HII regions, one UC HII region and four extended regions. The total integrated flux of the radio continuum emission at 5.5GHz is ~ 180Jy corresponding to a Lyman continuum output of 2.4x10^50^photons/s. We compare the ionized and molecular environment with optically identified high-mass stars and ongoing star formation, identified from the literature. Analysis of this data set reveals a star formation rate of 0.008-0.016M_{sun}_/yr and efficiency of 7-12%, allows us to probe the star formation history of the region and discuss the impact of high-mass stars on the evolution of G305.2013MNRAS.435.2003Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/435/2003CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/435/2003https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/435/2003http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/435/2003https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/435/2003https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/435/2003http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/435/2003GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/435/2003/clumps (Observed (table3) and physical (table4) properties of the 156 ^13^CO clumps detected within G305)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/435/2003/clumps?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/435/2003/clumps?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/435/2003/clumps?GETtext/xml+votable180.050000true197.8667-62.5220.0055555555555555566/41653 41655 41661https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/435/2003?format=asciiOpticalRadiodefaultJ/MNRAS/435/2003/clumpsObserved (table3) and physical (table4) properties of the 156 ^13^CO clumps detected within G305Seq[1/156] Clump sequential number <[HTU2013] NNN> in Simbadmeta.recordintprimaryNameClump Name (GLLL.ll+B.bb)meta.id;meta.maincharGLONPeak Galactic longitudedegpos.galactic.lonGLATPeak Galactic latitudedegpos.galactic.latVlsr[-48/-17] LSR clump velocitykm/sphys.veloc;pos.lsrfloatdGlon[38/170] Dimension along galactic longitude (1)arcsecphys.angSize;srcfloatdGlat[37/240] Dimension along galactic latitude (1)arcsecphys.angSize;srcfloatReffEffective radiuspcphys.size.radiusfloatdVlsr[0.9/5.7] Dimension along LSR velocity (1)km/sphys.angSize;srcfloatTb[1.9/15.4] Peak brightness temperatureKphys.temperaturefloattau[0.18/0.86] ^13^CO optical depthphys.absorption.opticalDepthfloate_tau[0.01/2.08] rms uncertainty on taustat.errorfloatTex[7/25] Excitation temperatureKphys.atmol.excitationfloate_Tex[0.09/0.28] rms uncertainty on TexKstat.errorfloatNH2[0.1/4.1] H_2_ clump density1e+22cm**-2phys.densityfloate_NH2[0.02/0.2] rms uncertainty on NH21e+22cm**-2stat.error;phys.columnDensityfloatnH2[0.3/4.5] H_2_ density numbercm**-3meta.number;phys.densityinte_nH2[0.2/2.2] rms uncertainty on nH2cm**-3stat.errorintSc[0.3/9.1] Surface mass density {Sigma}_c_solMass.pc**-2phot.flux.density.sbinte_Sc[0.1/2.9] rms uncertainty on ScsolMass.pc**-2stat.errorintM[0.1/23] Clump masssolMassphys.massinte_M[0.1/1.1] rms uncertainty on MsolMassstat.errorintMvir[0.2/19] Virial mass M_vir_solMassphys.massinte_Mvir[0.1/9.5] rms uncertainty on MvirsolMassstat.errorintavir[0.2/11.7] Ratio {alpha}_vir_ of the internal supporting energy to the gravitational energy (M_vir_/M)phys.mass;arith.ratiofloate_avir[0.1/6.2] rms uncertainty on alphavirstat.errorfloatSimbadSimbad column added by the CDSmeta.ref.urlchar_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data)degpos.eq.decnullableindexed