Temperature and Density Gradients Across the Nucleus of M82

Abstract

This paper presents 12CO J=3-2, 13CO J=3-2, C18O J=3-2, and 13CO J=2-1 spectra of the irregular starburst galaxy M82 taken with the 15 m James Clerk Maxwell Telescope. All maps exhibit a double peaked morphology, despite evidence that the higher J transitions are optically thick. This morphology suggests that the double peaked structure is not the result of an edge-on torus of molecular gas as is commonly assumed. We observe line ratio gradients that can best be explained by a temperature gradient increasing from NE to SW in conjunction with a density gradient that increases in the opposite sense. These gradients may have been caused by the interaction with M81, resulting in increased star formation that both heats and depletes the molecular gas in the SW lobe of M82.

8 pages + 2 colour figures; accepted for ApJ Letters

References in corpus (5)

• Dense Molecular Gas Associated with the Circumnuclear Star Forming Ring in the Barred Spiral Galaxy NGC 6951
• The Physical Conditions and Dynamics of the Interstellar Medium in the Nucleus of M83: Observations of CO and CI
• OH Satellite Line Masers and an AGN Candidate in M82
• The Effect of Star Formation on Molecular Clouds in Dwarf Irregular Galaxies: IC 10 and NGC 6822
• HCO+ in the Starburst Galaxy M82

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