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dc.creatorWu, Jingwenen_US
dc.creatorEvans, Neal J., IIen_US
dc.creatorShirley, Yancy L.en_US
dc.creatorKnez, Claudiaen_US
dc.date.accessioned2016-10-28T19:35:34Z
dc.date.available2016-10-28T19:35:34Z
dc.date.issued2010-06en_US
dc.identifierdoi:10.15781/T2GB1XK4Z
dc.identifier.citationWu, Jingwen, Neal J. Evans II, Yancy L. Shirley, and Claudia Knez. "The Properties of Massive, Dense Clumps: Mapping Surveys of HCN and CS." The Astrophysical Journal Supplement Series, Vol. 188, No. 2 (Jun., 2010): 313.en_US
dc.identifier.issn0067-0049en_US
dc.identifier.urihttp://hdl.handle.net/2152/42979
dc.description.abstractWe have mapped over 50 massive, dense clumps with four dense gas tracers: HCN J = 1-0 and 3-2; and CS J = 2-1 and 7-6 transitions. Spectral lines of optically thin H(13)CN 3-2 and C(34)S 5-4 were also obtained toward the map centers. These maps usually demonstrate single well-peaked distributions at our resolution, even with higher J transitions. The size, virial mass, surface density, and mean volume density within a well-defined angular size ( FWHM) were calculated from the contour maps for each transition. We found that transitions with higher effective density usually trace the more compact, inner part of the clumps but have larger linewidths, leading to an inverse linewidth-size relation using different tracers. The mean surface densities are 0.29, 0.33, 0.78, 1.09 g cm(-2) within FWHM contours of CS 2-1, HCN 1-0, HCN 3-2, and CS 7-6, respectively. We find no correlation of L(IR) with surface density and a possible inverse correlation with mean volume density, contrary to some theoretical expectations. Molecular line luminosities L'(mol) were derived for each transition. We see no evidence in the data for the relation between L'(mol) and mean density posited by modelers. The correlation between L'(mol) and the virial mass is roughly linear for each dense gas tracer. No obvious correlation was found between the line luminosity ratio and infrared luminosity, bolometric temperature, or the L(IR)/M(Vir) ratio. A nearly linear correlation was found between the infrared luminosity and the line luminosity of all dense gas tracers for these massive, dense clumps, with a lower cutoff in luminosity at L(IR) = 10(4.5) L(circle dot). The L(IR)-L'(HCN1-0) correlation agrees well with the one found in galaxies. These correlations indicate a constant star Formation rate per unit mass from the scale of dense clumps to that of distant galaxies when the mass is measured for dense gas. These results support the suggestion that starburst galaxies may be understood as having a large fraction of gas in dense clumps.en_US
dc.description.sponsorshipSubmillimeter Array of the Smithsonian Observatoryen_US
dc.description.sponsorshipNSF AST-0607793en_US
dc.description.sponsorshipMcDonald Observatoryen_US
dc.language.isoEnglishen_US
dc.relation.ispartofen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.subjectgalaxies: Formationen_US
dc.subjectism: cloudsen_US
dc.subjectism: moleculesen_US
dc.subjectstars: Formationen_US
dc.subjectsubmillimeter: ismen_US
dc.subjectstar-Formation rateen_US
dc.subjectluminous infrared galaxiesen_US
dc.subjectmolecular cloud coresen_US
dc.subjectcompact hii-regionsen_US
dc.subjecth-ii regionsen_US
dc.subjectprotostellar candidatesen_US
dc.subjectphysicalen_US
dc.subjectconditionsen_US
dc.subjectcontinuum observationsen_US
dc.subjectdust continuumen_US
dc.subjectouter galaxyen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleThe Properties of Massive, Dense Clumps: Mapping Surveys of HCN and CSen_US
dc.typeArticleen_US
dc.description.departmentAstronomyen_US
dc.rights.restrictionOpenen_US
dc.identifier.doi10.1088/0067-0049/188/2/313en_US
dc.contributor.utaustinauthorEvans, Neal J., IIen_US
dc.relation.ispartofserialAstrophysical Journal Supplement Seriesen_US


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