Light scattering and extinction in M82

The appearance of the irregular galaxy M82 is to a large extent determined by the interaction of dust with the light from various constituents of the galaxy. The considered investigation represents an attempt to combine evidence from both photometry and polarimetry studies to derive more detailed data on the distribution of the dust, the properties of the illuminating source, and the geometrical characteristics of the illumination. On the basis of the available data, it appears that a single central source is responsible for most of the illumination of the dust. Two independent crude estimates are provided for the relative brightness of the core. It is concluded that the central source is the strongest contributor to the scattered light at medium distances from the major axis and near the minor axis. A brightness relation nucleus:disk near 1:1 is probable. Attention is also given to the undiluted polarization, the stellar population, and the extinction characteristics.