Known and Unknown Scuba Sources

The sub-mm waveband has opened up for cosmology, and through this window we can hope to glimpse some answers to a number of related puzzles: What are the brightest sub-mm galaxies? What sorts of galaxies make up the Far-IR Background (FIB)? When did the Universe form the bulk of its stars? How important is dust obscuration for obtaining a full star-formation census? SCUBA has been instrumental in establishing this new field of sub-mm high redshift astronomy. This meeting has been dominated by SCUBA-based surveys, and stands as a testament to the instrument builders who produced the best camera of its kind at just the right time. Many basic questions have already been answered by the SCUBA data which are in hand, and a coherent picture has developed – typical SCUBA sources are the z∼ 2–3 counterparts of locally well-studied Ultraluminous Infrared Galaxies, and these are considerably more common at an epoch which was perhaps important for the formation of elliptical galaxies. However, there are still a great many details to understand about the exact composition of the SCUBA-bright sources, including how they overlap with populations selected at other wavelengths, how the ∼mJy sources might differ from the brighter ones, what the clustering strength of the SCUBA sources might be, and what fraction could be at still higher redshifts. Here we will avoid reviewing all of the different studies (many of which are covered in other presentations), but