NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-06-18 T22:20:53 PDT
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For refcode 2008ApJ...673..832M:
Retrieve 19 NED objects in this reference.
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Copyright by American Astronomical Society. Reproduced by permission
2008ApJ...673..832M Formaldehyde Densitometry of Starburst Galaxies Mangum, Jeffrey G.; Darling, Jeremy; Menten, Karl M.; Henkel, Christian Abstract. With a goal toward deriving the physical conditions in external galaxies, we present a survey of the formaldehyde emission in a sample of starburst systems. By extending a technique used to derive the spatial density in star formation regions in our own Galaxy, we show how the relative intensity of the 1_10_-1_11_ and 2_11_-2_12_ K-doublet transitions of H_2_CO can provide an accurate densitometer for the active star formation environments found in starburst galaxies. Relying on an assumed kinetic temperature and cospatial emission and absorption from both H_2_CO transitions, our technique is applied to a sample of 19 infrared-bright galaxies which exhibit various forms of starburst activity. In the five galaxies of our sample where both H_2_CO transitions were detected, we have derived spatial densities. We also use H_2_CO to estimate the dense gas mass in our starburst galaxy sample, finding similar mass estimates for the dense gas-forming stars in these objects as derived using other dense gas tracers. A related trend can be seen when one compares L_IR_ to our derived n(H_2_) for the five galaxies within which we have derived spatial densities. Even though our number statistics are small, there appears to be a trend toward higher spatial density for galaxies with higher infrared luminosity. This is likely another representation of the L_IR_-M_dense_ correlation. Key words: Galaxies: Starburst, ISM: Molecules
Retrieve 19 NED objects in this reference.
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