Hiroshi Matsuo
National Astronomical Observatory, Japan
Astro-F or IRIS (Infrared Imaging Surveyer) is a Japanese infrared satellite with 70cm liquid Helium cooled telescope planned to be launched in 2003. On board are near-infrared and middle-infrared imaging arrays (IRC) and a far-infrared survey instrument (FIS). Both instruments also have spectroscopic capability. During the first half year period, the Astro-F will concentrate on the all sky survey at four wave-bands in the far-infrared and it is expected that more than 106 galaxies will be observed. Among the galaxies more than 1000 will have redshift larger than 1.0.
The galaxies detected by the Astro-F FIS instrument will be the largest database of distant galaxies at the time when ALMA start operation. A strategy for extracting the most distant galaxies is as follows. First the FIS colors are used to pre-select candidate galaxies. Next submillimeter-wave observations determine their photometric redshifts. Then spectroscopic observaions of far-infrared lines are made in submillimeter-wave. After all these, ALMA observations will reveal the formation and evolution of the most distant galaxies.