A Simple Model For Mid-Infrared Emission from Normal Galaxies

We have combined up-to-date stellar population synthesis models, a simple radiative transfer approach, and a fully comprehensive dust model with the aim of developing a simple but quantitative way of interpreting the mid-infrared spectra of galaxies. We apply these models to the observed correlations of mid-infrared luminosities (at 8 and 24 micron) with the star-formation rate of normal galaxies and find that the observations are naturally reproduced by our models. We further find that the observed 24 micron correlation places a weak constraint on relative distribution of dust and stars.