Extremely Red Galaxies: Old or Dusty ?

Abstract

The nature of the extremely red galaxies is poorly known, the critical issue being whether they are old ellipticals at $z>1.5$ or distant star-forming galaxies strongly reddened by dust extinction. Here we review the little we know about them, and we present recent and preliminary results from our ongoing submillimeter -- millimeter observations.

4 pages, 1 figure. To appear in the proceedings of the Xth Rencontres de Blois: The Birth of Galaxies; Blois, France, July 1998