A deep ISOCAM survey in the SSA13

¹ Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan
² Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
³ Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba Sendai 980-8578, Japan
⁴ Institute of Space and Astronautical Sciences, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan
⁵ Gunma Astronomical Observatory, 6860-86 Nakayama, Takayama, Agatsuma, Gunma 377-0702, Japan
⁶ Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan

Corresponding author: ysato@ioa.s.u-tokyo.ac.jp

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.