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dc.contributor.authorAnderson, L. D.
dc.contributor.authorBania, T. M.
dc.contributor.authorJackson, James M.
dc.contributor.authorClemens, D. P.
dc.contributor.authorHeyer, Mark
dc.contributor.authorSimon, R.
dc.contributor.authorRathborne, J. M.
dc.contributor.authorShah, Ronak
dc.date.accessioned2015-03-12T20:18:27Z
dc.date.available2015-03-12T20:18:27Z
dc.date.issued2009-03
dc.date.submitted2008-08
dc.identifier.issn0067-0049
dc.identifier.issn1538-4365
dc.identifier.urihttp://hdl.handle.net/1721.1/96001
dc.description.abstractWe derive the molecular properties for a sample of 301 Galactic H II regions including 123 ultra compact (UC), 105 compact, and 73 diffuse nebulae. We analyze all sources within the BU-FCRAO Galactic Ring Survey (GRS) of [superscript 13]CO emission known to be H II regions based upon the presence of radio continuum and cm-wavelength radio recombination line emission. Unlike all previous large area coverage [superscript 13]CO surveys, the GRS is fully sampled in angle and yet covers ~75 deg[superscript 2] of the Inner Galaxy. The angular resolution of the GRS (46'') allows us to associate molecular gas with H II regions without ambiguity and to investigate the physical properties of this molecular gas. We find clear CO/H II morphological associations in position and velocity for ~80% of the nebular sample. Compact H II region molecular gas clouds are on average larger than UC clouds: 2'2 compared to 1'7. Compact and UC H II regions have very similar molecular properties, with ~5 K line intensities and ~4 km s[superscript –1] line widths. The diffuse H II region molecular gas has lower line intensities, ~3 K, and smaller line widths, ~3.5 km s[superscript –1]. These latter characteristics are similar to those found for quiescent molecular clouds in the GRS. Our sample nebulae thus show evidence for an evolutionary sequence wherein small, dense molecular gas clumps associated with UC H II regions grow into older compact nebulae and finally fragment and dissipate into large, diffuse nebulae.en_US
dc.description.sponsorshipNational Science Foundation (U.S.) (Grant AST-9800334)en_US
dc.description.sponsorshipNational Science Foundation (U.S.) (Grant AST-0098562)en_US
dc.description.sponsorshipNational Science Foundation (U.S.) (Grant AST-0100793)en_US
dc.description.sponsorshipNational Science Foundation (U.S.) (Associated Universities, Inc. Cooperative Research Agreement)en_US
dc.description.sponsorshipNational Radio Astronomy Observatory (U.S.)en_US
dc.language.isoen_US
dc.publisherIOP Publishingen_US
dc.relation.isversionofhttp://dx.doi.org/10.1088/0067-0049/181/1/255en_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.sourceAmerican Astronomical Societyen_US
dc.titleTHE MOLECULAR PROPERTIES OF GALACTIC H II REGIONSen_US
dc.typeArticleen_US
dc.identifier.citationAnderson, L. D., T. M. Bania, J. M. Jackson, D. P. Clemens, M. Heyer, R. Simon, R. Y. Shah, and J. M. Rathborne. “THE MOLECULAR PROPERTIES OF GALACTIC H II REGIONS.” The Astrophysical Journal Supplement Series 181, no. 1 (March 1, 2009): 255–271. © 2009 The American Astronomical Societyen_US
dc.contributor.departmentLincoln Laboratoryen_US
dc.contributor.mitauthorShah, Ronaken_US
dc.relation.journalAstrophysical Journal. Supplement Seriesen_US
dc.eprint.versionFinal published versionen_US
dc.type.urihttp://purl.org/eprint/type/JournalArticleen_US
eprint.statushttp://purl.org/eprint/status/PeerRevieweden_US
dspace.orderedauthorsAnderson, L. D.; Bania, T. M.; Jackson, J. M.; Clemens, D. P.; Heyer, M.; Simon, R.; Shah, R. Y.; Rathborne, J. M.en_US
mit.licensePUBLISHER_POLICYen_US
mit.metadata.statusComplete


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