VLA observations of extragalactic NH/sub 3/ in IC 342

Journal Article · Thu Sep 15 04:00:00 EDT 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/161315· OSTI ID:5337565

Ho, P T.P.; Martin, R N

Aperture synthesis maps of the nuclear region in the nearby spiral IC 342 were made in the (J, K)-(1, 1) and (2, 2) inversion lines of NH/sub 3/. NH/sub 3/ emission was not detected with an upper limit to the apparent brightness temperature of 0.5 K (referred to 6'' resolution). Comparison with single-dish measurements indicates that the NH/sub 3/ emission in the nucleus of IC 342 must be distributed on a size scale greater than 130 pc. We interpret these results as favoring a model where the NH/sub 3/ emission is moderately optically thick, thermalized to a gas temperature of approx.50 K, and clumpy. This is consistent with a high OB star-formation rate in the nucleus accompanied by heated dust and gas.

• Research Organization: Radio Astronomy Laboratory, University of California, Berkeley and Harvard-Smithsonian Center for Astrophysics
• OSTI ID: 5337565
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 272:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

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640105* -- Astrophysics & Cosmology-- Galaxies
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