Modelling the spectral energy distribution of galaxies from the ultraviolet to submillimeter

Abstract

We present results from a new modelling technique which can account for the observed optical/NIR - FIR/submm spectral energy distributions (SEDs) of normal star-forming galaxies in terms of a minimum number of essential parameters specifying the star-formation history and geometrical distribution of stars and dust. The model utilises resolved optical/NIR images to constrain the old stellar population and associated dust, and geometry-sensitive colour information in the FIR/submm to constrain the spatial distributions of young stars and associated dust. It is successfully applied to the edge-on spirals NGC891 and NGC5907. In both cases the young stellar population powers the bulk of the FIR/sub-mm emission. The model also accounts for the observed surface brightness distribution and large-scale radial brightness profiles in NGC891 as determined using the Infrared Space Observatory (ISO) at 170 and 200 mcrions and at 850 micron using SCUBA.