ASTRO-F - The next generation of mid-infrared surveys

We present basic observational strategies for ASTRO-F (also known as the Imaging Infra Red Surveyor (IRIS)) to be launched in 2004 by the Japanese Institute of Space and Astronautical Science (ISAS). We examine 2 survey scenarios, a deep ~1sq.deg. survey reaching sensitivities an order of magnitude below than the deepest surveys performed by ISO in the mid-IR, and a shallow \~18sq.deg mid-infrared (7-25um in 6 bands) covering an area greater than the entire area covered by all ISO mid-IR surveys. Using 2 cosmological models the number of galaxies predicted for each survey is calculated. The first model uses an enhancement of the pure luminosity evolution model of Pearson&Rowan-Robinson while the new models incorporate a strongly evolving ULIG component. For the deep survey, between 20,000-30,000 galaxies should be detected in the shortest wavebands and ~5000 in the longest (25um) band. The shallow survey would be expected to detect of the order of 100,000 - 150,000 sources.