Infrared Camera (IRC) Deep Survey in the Performance-Verification Phase

Abstract

Abstract We report on the first results of a near- and mid-infrared deep survey with the Infrared Camera (IRC) onboard AKARI in the performance-verification phase. Simultaneous observations by the Near-InfraRed (NIR), Mid-InfraRed Short (MIR-S), and Mid-InfraRed Long (MIR-L) channels of the IRC with effective integration times of 4529, 4908, and 4417 seconds at 3, 7, and 15$\mu $m, covering 86.0, 70.3, and 77.3 arcmin$^2$ area, detected 955, 298, and 277 sources, respectively. The 5 $\sigma$ detection limits of the survey are 6.0, 31.5, and 71.2$\mu $Jy and the 50% completeness limit are 24.0, 47.5, and 88.1$\mu $Jy at 3, 7, and 15$\mu $m, respectively. Observation are limited by source confusion at 3$\mu $m. We have confirmed the turnover in the 15$\mu $m differential source counts around 400$\mu $Jy, previously detected by surveys with the Infrared Space Observatory. The faint end of 15$\mu $m raw source counts agrees with those from deep surveys in the GOODS fields, carried out with the Spitzer IRS peak up imager and predictions of current galaxy evolution models. These results indicate that deep surveys with comprehensive wavelength coverage at mid-infrared wavelength are very important to investigate the evolution of infrared galaxies at high redshifts.