A deep ISOCAM survey in the SSA13

Abstract

We present initial results of a deep mid-infrared survey conducted in the high galactic latitude field SSA13 with ISO. We have surveyed through the broad band filter LW2 (5-8.5 μm) of the mid-infrared camera ISOCAM to probe the near-infrared light at high redshift. The 80% completeness limit for point sources in the central 6 arcmin2 reaches 10 μJy at 6.7 μm. 65 sources are detected down to 6 μJy in 16 arcmin2. The integral galaxy number counts are 1.4 × 104 deg-2 at 10 μJy with the slope of -1.5. The integrated 6.7 μm light down to 6 μJy is estimated as 0.43 nWm-2sr-1. Our counts are consistent with the results in the HDF and the model prediction based on the K band local luminosity function. It suggests that the majority of the detected sources are E/S0 galaxies at z>1.