1995A&A...300...20B

A new method of searching for high redshift objects (z>5) is proposed. It is shown that observations at 100 and 230GHz provide the most powerful means of searching for protogalaxies which emit most of their radiation in the far infra-red (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 project. Protogalaxies invisible to IRAS and much weaker than IRAS 10214+4724 can be detected. Unlike low frequency radio observations, confusion is not a problem. Based on the current number density of bright ellipticals, a reasonable guess for the current evolutionary state of systems similar to IRAS 10214+4724, the expected number of sources per square arcminute between z=5 and z=15 is close to unity. The number is not very sensitive to the redshift limits chosen.