IRAC Observations of M81
Abstract
IRAC images of M81 show three distinct morphological constituents: a smooth distribution of evolved stars with bulge, disk, and spiral arm components; a clumpy distribution of dust emission tracing the spiral arms; and a pointlike nuclear source. The bulge stellar colors are consistent with M-type giants, and the disk colors are consistent with a slightly younger population. The dust emission generally follows the blue and ultraviolet emission, but there are large areas that have dust emission without ultraviolet and smaller areas with ultraviolet but little dust emission. The former are presumably caused by extinction, and the latter may be due to cavities in the gas and dust created by supernova explosions. The nucleus appears fainter at 8 um than expected from ground-based 10 um observations made four years ago.
Keywords
Cite
@article{arxiv.astro-ph/0405626,
title = {IRAC Observations of M81},
author = {S. P. Willner and M. L. N. Ashby and P. Barmby and G. G. Fazio and M. Pahre and H. A. Smith and R. C. Kennicutt, and D. Calzetti and D. A. Dale and B. T. Draine and M. W. Regan and S. Malhotra and M. D. Thornley and P. N. Appleton and D. Frayer and G. Helou and S. Stolovy and L. Storrie-Lombardi},
journal= {arXiv preprint arXiv:astro-ph/0405626},
year = {2012}
}
Comments
ApJS in press (Spitzer special issue); 15 pages, 3 figures. Changes: unused references removed, numbers and labels in Table 1 changed