Gemini Preprint #4

The Spatial Distribution of Stellar CO Absorption in M83

P. Puxley
Gemini 8m Telescopes Project, 950 N. Cherry Ave., Tucson AZ 85719

R. Doyon
Dept. de Physique, Univ. de Montreal, CP 6128, Succ. Centre-ville, Montreal (QC), H3C 3J7, Canada

M. J. Ward
Dept. of Astrophysics, Univ. of Oxford, Keble Road, Oxford, OX1 3RH, UK


Long slit H- and K-band near-infrared spectra have been acquired through the bright nuclear starburst region in the nearby galaxy M83. The spatial distribution of the stellar CO 2-0 absorption band broadly resembles that of the 2µm continuum emission and has a maximum depth consistent with a pure starburst population. The band strength deceases monotonically away from this location to a value consistent with that seen in the giant-dominated populations in ellipticals and the bulges of spiral galaxies. There is no significant variation in the ratio of H (CO 6-3) and K (CO 2-0) band equivalent widths which argues against any significant dilution of the bands by hot dust. The CO depth and Brgamma emission line equivalent width are anti-correlated. Comparison with starburst evolutionary models indicates an age gradient across this central region.

Submitted to the Astrophysical Journal.

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Ruth A. Kneale / / November 15, 1996