J/A+A/489/533ivo://CDS.VizieR/J/A+A/489/533doi:10.26093/cds/vizier.34890533CDSHeiner J.S.Allen R.J.Ivy Wong O.van der Kruit P.C.2018-01-30T07:18:08Z2008-11-23T18:47:47ZCDS support team

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

cds-question@unistra.frgalaxiesmolecular-cloudsultraviolet-astronomyradio-astronomyUsing observed GALEX far-ultraviolet (FUV) fluxes and VLA images of the 21-cm HIcolumn densities, along with estimates of the local dust abundances, we measure the volume densities of a sample of actively star-forming giant molecular clouds (GMCs) in the nearby spiral galaxy M83 on a typical resolution scale of 170 pc. Our approach is based on an equilibrium model for the cycle of molecular hydrogen formation on dust grains and photodissociation under the influence of the FUV radiation on the cloud surfaces of GMCs. We find a range of total volume densities on the surface of GMCs in M83, namely 0.1-400cm^-3^ inside R_25_, 0.5-50cm^-3^ outside R_25_. Our data include a number of GMCs in the HI-ring surrounding this galaxy. Finally, we discuss the effects of observational selection, which may bias our results.2008A&A...489..533Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/489/533CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJS/149/343 : Giant molecular clouds in M33 (Engargiola+, 2003)J/A+A/426/119 : RCW 106 Giant Molecular Cloud 1.2mm maps (Mookerjea+, 2004)J/MNRAS/353/1025 : JHK photometry of 4 W51 star clusters (Nanda+, 2004)J/MNRAS/367/1609 : RCW 106 Giant Molecular Cloud 13CO mapping (Bains+, 2006)J/MNRAS/379/663 : W3 giant molecular cloud 850um observations (Moore+, 2007)J/A+A/471/103 : SIMBA observations of SMC (Bot+, 2007)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/489/533https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/489/533http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/489/533https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/489/533https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/489/533http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/489/533GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/489/533/table1 (Locations and FUV fluxes of candidate photodissociation regions (PDRs))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/489/533/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/489/533/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/489/533/table1?GETtext/xml+votable180.050000true204.25560833-29.879088890.0055555555555555566/43881https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/489/533?format=asciiUVRadiodefaultJ/A+A/489/533/table1Locations and FUV fluxes of candidate photodissociation regions (PDRs)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/76] Source numbermeta.id;meta.mainintprimaryRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainRgalGalactocentric radiuskpcpos.distance;pos.galactocentricfloatFFUVFUV Flux (in 10^-15^erg/cm^2^/s/{AA})1e-17W.m**-2.nm**-1phot.flux;em.UVfloatApAperturearcsecphys.angSize;instr.fovintGrSGrayscale start1e+19cm**-2phys.columnDensityintIncGrayscale level increment (1)phys.columnDensityfloatJ/A+A/489/533/table3HI measurements, incident fluxes and volume densitiesG0Incident flux G0phot.flux;em.UVfloatSeq[1/76] Source numbermeta.id;meta.mainintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintPatch[a-o] Patch number (letter)meta.code.multipcharrhoSeparation UV-HI patchpcpos.distance;arith.diffintNHIHI column density1e+20cm**-2phys.columnDensityfloatGGbgG/Gbg source contrastphot.flux;arith.ratiofloatnTotal H volume densitycm**-3phys.densityfloatErrFractional errorstat.errorfloat