A METHOD OF SEARCHING FOR HIGH-REDSHIFT PROTO-GALAXIES

A new method of searching for high redshift objects (z > 5) is propose d. It is shown that observations at 100 and 230 GHz provide the most p owerful means of searching for protogalaxies which emit most of their radiation in the far infrared (like IRAS 10214+4724). Not only has the sensitivity of millimeter-wave interferometers reached the necessary levels but the synthesized beam is also well adapted to this sort of p roject. Protogalaxies invisible to IRAS and much weaker than IRAS 1021 4+4724 can be detected. Unlike low frequency radio observations, confu sion is not a problem. Based on the current number density of bright e llipticals, a reasonable guess for the current evolutionary state of s ystems similar to IRAS 10214+4724, the expected number of sources per square arcminute between z = 5 and z = 15 is close to unity. The numbe r is not very sensitive to the redshift limits chosen.