J/ApJ/845/116ivo://CDS.VizieR/J/ApJ/845/116doi:10.26093/cds/vizier.18450116CDSWatanabe Y.Nishimura Y.Harada N.Sakai N.Shimonishi T.Aikawa Y.,Kawamura A.Yamamoto S.2018-06-19T08:49:16Z2018-05-14T15:52:04ZCDS support team

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

cds-question@unistra.frmolecular-cloudsradio-spectroscopyWe have conducted a mapping spectral line survey toward the Galactic giant molecular cloud W51 in the 3mm band with the Mopra 22m telescope in order to study an averaged chemical composition of the gas extended over a molecular-cloud scale in our Galaxy. We have observed the area of 25'x30', which corresponds to 39pcx47pc. The frequency ranges of the observation are 85.1-101.1GHz and 107.0-114.9GHz. In the spectrum spatially averaged over the observed area, spectral lines of 12 molecular species and 4 additional isotopologues are identified. An intensity pattern of the spatially averaged spectrum is found to be similar to that of the spiral arm in the external galaxy M51, indicating that these two sources have similar chemical compositions. The observed area has been classified into five subregions according to the integrated intensity of ^13^CO(J=1-0) (I_13CO_), and contributions of the fluxes of 11 molecular lines from each subregion to the averaged spectrum have been evaluated. For most of the molecular species, 50% or more of the flux comes from the subregions with I_13CO_ from 25 to 100K.km.s^-1^, which does not involve active star-forming regions. Therefore, the molecular-cloud-scale spectrum observed in the 3mm band hardly represents the chemical composition of star-forming cores, but mainly represents the chemical composition of an extended quiescent molecular gas. The present result constitutes a sound base for interpreting the spectra of external galaxies at a resolution of a molecular-cloud scale (~10pc) or larger.2017ApJ...845..116Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/845/116CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/AJ/127/2031 : Catalog of neighboring galaxies (Karachentsev+, 2004)J/A+A/455/971 : Organic molecules in the Gal. Center (Requena-Torres+, 2006)J/ApJS/178/56 : CO observations of LMC Giant Molecular clouds (Fukui+, 2008)J/ApJS/191/232 : CO survey of W51 molecular cloud (Bieging+, 2010)J/ApJ/709/424 : HII regions identified with WMAPS and GLIMPSE (Murray+, 2010)J/ApJ/720/1055 : VBLA observations of W51 Main/South (Sato+, 2010)J/AJ/147/131 : Abundances of nearby late-type galaxies. I. (Pilyugin+, 2014)J/A+A/579/A101 : 3mm molecular line survey of 8 AGN (Aladro+, 2015)J/A+A/582/A91 : NGC 4418 ALMA mm-wave spectral scan (Costagliola+, 2015)J/A+A/582/A64 : W51/e2 and G34.3+0.2 IRAM spectra (Lykke+, 2015)J/A+A/595/A27 : JVLA images of W51A (Ginsburg+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/845/116https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/845/116http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/845/116https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/845/116https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/845/116http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/845/116GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapRadiodefaultJ/ApJ/845/116/table8Line parameters of W51 e1/e2recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLineLine identifier (1)meta.id;spect.linef_LineFlag(s) on Line (2)meta.codecharFreq[85.2/114.1] FrequencyGHzem.freqdoubleTransTransitionmeta.id;phys.atmol.transitioncharEu[4/1490.1]? Upper state energyKphys.energyfloatnullableSmu2[0.01/386.3]? Dipole moment line strengthD**2phys.mol.dipolefloatnullableTmb[0.06/20.3]? Peak main beam temperatureKphys.temperature;meta.main;stat.maxfloatnullablee_Tmb[0.04/0.2]? The 3{sigma} uncertainty in TmbKstat.errorfloatnullableInt[0.2/250]? Integrated intensityK.km/sphot.flux.density;em.radiofloatnullablee_Int[0.2/2]? The 3{sigma} uncertainty in IntK.km/sstat.errorfloatnullableJ/ApJ/845/116/fig2Spectra averaged over all the observed area in W51 and W51 e1/e2 (hot cores)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegRegion identifier (1)meta.codecharFreq[85/115] Rest frequency (2)GHzem.freqdoubleTmb[-0.5/20.3] Main beam temperatureKphys.temperature;meta.maindoubleJ/ApJ/845/116/fig5Averaged spectra in the sub-regions A, B, C, D, and ErecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintReg[A-E] Region identifier (1)meta.codecharFreq[85/115] Rest frequency at the LSR velocity of 55km/sGHzem.freqdoubleTmb[-0.3/14.7] Main beam temperatureKphys.temperature;meta.maindouble