J/A+A/598/A30ivo://CDS.VizieR/J/A+A/598/A30doi:10.26093/cds/vizier.35980030CDSTang X.D.Henkel C.Menten K.M.Zheng X.W.Esimbek J.Zhou J.J.,Yeh C.C.Konig C.Yuan Y.He Y.X.Li D.L.2022-11-22T15:32:08Z2017-01-26T07:43:59ZCDS support team

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

cds-question@unistra.frmolecular-cloudsspectroscopyradio-astronomyFor a general understanding of the physics involved in the star formation process, measurements of physical parameters such as temperature and density are indispensable. The chemical and physical properties of dense clumps of molecular clouds are strongly affected by the kinetic temperature. Therefore, this parameter is essential for a better understanding of the interstellar medium. Formaldehyde, a molecule which traces the entire dense molecular gas, appears to be the most reliable tracer to directly measure the gas kinetic temperature.We aim to determine the kinetic temperature with spectral lines from formaldehyde and to compare the results with those obtained from ammonia lines for a large number of massive clumps.Three 218 GHz transitions (J_KAKC_=3_03_-2_02_, 3_22_-2_21_, and 3_21_-2_20_) of para-H_2_CO were observed with the 15m James Clerk Maxwell Telescope (JCMT) toward 30 massive clumps of the Galactic disk at various stages of high-mass star formation. Using the RADEX non-LTE model, we derive the gas kinetic temperature modeling the measured para-H_2_CO 3_22_-2_21_/3_03_-2_02_ and 3_21_-2_20_/3_03_-2_02_ ratios. The gas kinetic temperatures derived from the para-H2CO (3_21_-2_20_/3_03_-2_02_) line ratios range from 30 to 61K with an average of 46K. A comparison of kinetic temperature derived from para-H_2_CO, NH3, and the dust emission indicates that in many cases para-H_2_CO traces a similar kinetic temperature to the NH_3_ (2,2)/(1,1) transitions and the dust associated with the HII regions. Distinctly higher temperatures are probed by para-H_2_CO in the clumps associated with outflows/shocks. Kinetic temperatures obtained from para-H_2_CO trace turbulence to a higher degree than NH_3_ (2,2)/(1,1) in the massive clumps. The non-thermal velocity dispersions of para-H_2_CO lines are positively correlated with the gas kinetic temperature. The massive clumps are significantly influenced by supersonic non-thermal motions.2017A&A...598A..30Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/598/A30CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/598/A30https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/598/A30http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/598/A30https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/598/A30https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/598/A30http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/598/A30GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/598/A30/table1 (Source parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/598/A30/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/598/A30/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/598/A30/table1?GETtext/xml+votable180.050000true270.1264167-24.0667250.0055555555555555566/28890 28912-28913 28919 29090 29094-29095 29097 29101 29112-29113 29115 29118 29463 29505 29510 29532 30258 30262-30263 30268 30316 30319 30405 304202.283270615984385e-22 2.283270615984385e-22https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/598/A30?format=asciiRadiodefaultJ/A+A/598/A30/table1Source parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource name (GLL.ll+B.bb)meta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainN(NH3)NH_3_ column density1e+15cm**-2phys.columnDensityfloatN(NH2)? NH_2_ column density1e+22cm**-2phys.columnDensityfloatnullableS870umFlux density at 870umJyphot.flux.density;em.mm.200-400GHzfloatTkinNH3Kinetic temperature from NH_3_Kphys.temperaturefloate_TkinNH3rms uncertainty on TkinNH3Kstat.errorfloatTdust? Kinematic temperature from dust(HiGal)Kphys.temperaturefloatnullablee_Tdust? rms uncertainty on TdustKstat.errorfloatnullableDistDistancekpcpos.distance;pos.heliocentricfloatAssocAssociation (1)src.classcharsp1CH_3_OH spectrummeta.ref.urlcharsp2para-H_2_CO 3_03_-2_02_ spectrummeta.ref.urlcharsp3para-H_2_CO 3_21_-2_20_ spectrummeta.ref.urlcharsp4para-H_2_CO 3_22_-2_21_ spectrummeta.ref.urlcharSp1Fits filename of CH_3_OH spectra in sp subdirectorymeta.id;meta.filecharSp2Fits filename of H_2_CO 3_03_-2_02_ spectra in sp subdirectorymeta.id;meta.filecharSp3Fits filename of H_2_CO 3_21_-2_20_ spectra in sp subdirectorymeta.id;meta.filecharSp4Fits filename of H_2_CO 3_22_-2_21_ spectra in sp subdirectorymeta.id;meta.filecharJ/A+A/598/A30/table2CH_3_OH(4_22_-3_12_) spectral parameterse_Vlsrrms uncertainty on Vlsrkm/sstat.error;phys.veloc;pos.lsrfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource name (GLL.ll+B.bb)meta.id;meta.maincharITmbdv? Integrated intensityK.km/sphot.flux.densityfloatnullablee_ITmbdv? rms uncertainty on ITmbdvK.km/sstat.errorfloatnullableVlsrLSR velocitykm/sphys.veloc;pos.lsrfloatFWHM? FWHMkm/sspect.line.widthfloatnullablee_FWHM? rms uncertainty on FWHMkm/sstat.error;phys.angSizefloatnullableTmb? Main beam brightness temperatureKphys.temperature;meta.mainfloatnullableJ/A+A/598/A30/table3Para-H_2_CO column densities and kinetic temperatureE_Tkin2? Error on Tkin2 (upper value)Kstat.error;stat.maxintnullablee_Tkin2? Error on Tkin2 (lower value)Kstat.errorintnullableTlte? =- LTE kinetic temperatureKspect.line.intensityintnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource name (GLL.ll+B.bb)meta.id;meta.maincharN(para-H2CO)para-H_2_CO column density for n(H_2_)-10^5^cm^-3^cm**-2phys.columnDensitydoubleTkin1? Kinetic temperature derived by para-H_2_CO (3_22_-2_21_/3_03_-2_02_)Kphys.temperatureintnullableE_Tkin1? Error on Tkin1 (upper value)Kstat.error;stat.maxintnullablee_Tkin1? Error on Tkin1 (lower value)Kstat.errorintnullableTkin2? Kinetic temperature derived by para-H_2_CO (3_21_-2_20_/3_03_-2_02_)Kphys.temperatureintnullableJ/A+A/598/A30/table5Thermal and non-thermal parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource name (GLL.ll+B.bb)meta.id;meta.maincharsigmaT1NH_3_ thermal line widthkm/sspect.line.widthfloatsigmaNT1NH_3_ non-thermal velocity dispersionkm/sspect.line.widthfloatas1NH_3_ thermal sound speedkm/sphys.velocfloatRp1NH_3_ ratio of thermal to nonthermal pressure (1)phys.pressure;arith.ratiofloatsigmaT2? H_2_CO thermal line widthkm/sspect.line.widthfloatnullablesigmaNT2? H_2_CO non-thermal velocity dispersionkm/sspect.line.widthfloatnullableas2? H_2_CO thermal sound speedkm/sphys.velocfloatnullableRp2? H_2_CO ratio of thermal to nonthermal pressure (2)phys.pressure;arith.ratiofloatnullableJ/A+A/598/A30/tablea2Para-H_2_CO spectral parametersTransTransitionmeta.id;phys.atmol.transitioniTmbdV? Integrated intensityK.km/sphot.flux.densityfloatnullablee_iTmbdV? rms uncertainty on iTmbdVK.km/sstat.errorfloatnullableVlsr? LSR velocitykm/sphys.veloc;pos.lsrfloatnullablee_Vlsr? rms uncertainty on Vlsrkm/sstat.error;phys.veloc;pos.lsrfloatnullableFWHM? FWHMkm/sspect.line.widthfloatnullablee_FWHM? rms uncertainty on FWHMkm/sstat.error;phys.angSizefloatnullableTmb? Main beam brightness temperatureKphys.temperature;meta.mainfloatnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource name (GLL.ll+B.bb)meta.id;meta.mainchar