Simulations of cosmological observations with ASTRO-F/FIS Original Research Article

The far-infrared surveyor (FIS) is one of the focal-plane instruments on the ASTRO-F mission which will be launched in early 2004. The purpose of the FIS is to perform an all-sky survey in the wavelength range 50–200 μm. We are developing a suite of software that simulates the observations with this instrument to check the performance of the ASTRO-F/FIS as a whole and to prepare input data sets for the data analysis and reduction software prior to launch. The detection limit of the FIS is affected by many factors: the performance of the entire system, the brightness of sky and telescope emission, readout process, and the distribution of the celestial sources. The input model for FIS simulator consists of a catalogue of extragalactic point sources generated from the luminosity function at 60 μm, and a redshift distribution incorporating pure luminosity evolution (Ω0=1, Λ=0). We present the expected source count results from the FIS survey and estimate the limiting redshift as ∼2.5 in the band at 50–110 μm and ∼3 in the band at 110–200 μm.