ASTRO-F: the next generation of mid-infrared surveys |
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| Authors: | CP Pearson † H Matsuhara T Onaka H Watarai T Matsumoto |
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| Institution: | ;1Institute of Space and Astronautical Science, Yoshinodai 3-1-1, Sagamihara, Kanagawa 229 8510, Japan;2Department of Astronomy, School of Science, University of Tokyo, Tokyo 113-0033, Japan |
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| Abstract: | We present basic observational strategies for ASTRO-F also known as the Infra-Red Imaging Surveyor (IRIS) ] to be launched in 2004 by the Japanese Institute of Space and Astronautical Science (ISAS). We examine two survey scenarios, a deep ～1 deg2 survey reaching sensitivities an order of magnitude below all but the deepest surveys performed by ISO in the mid-IR, and a shallow ～18 deg2 mid-IR (7–25μm in six bands) covering an area greater than the entire area covered by all ISO mid-IR surveys. Using two cosmological models, the number of galaxies predicted for each survey is calculated. The first model uses an enhancement of a classical (1+ z )3.1 pure luminosity evolution model by Pearson & Rowan-Robinson. The second model incorporates a strongly evolving ultraluminous infrared galaxy component. For the deep survey, between 20 000 and 30 000 galaxies should be detected in the shortest wavebands, and ≈5000 in the longest (25-μm) band. It is predicted that the shallow survey will detect of the order of 100 000–150 000 sources. We find that for both ASTRO-F and other small-aperture space telescopes, confusion due to faint sources may be severe, especially at the longest mid-IR wavelengths. Using the exceptional range of observational options provided by ASTRO-F (nine wavelength filters and spectroscopic ability from 2.2 to 25 μm), we show that by combining the mid-IR observations with the near-IR camera on ASTRO-F , both the different galaxy populations and rough photometric redshifts can be distinguished in the colour–colour plane. In its role as a surveyor (plus near-IR spectroscopic ability) ASTRO-F will complement well the SIRTF space observatory mission. |
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| Keywords: | surveys galaxies: evolution cosmology: observations infrared: galaxies |
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