Deep submillimeter surveys: Luminous infrared galaxies at high redshift

Deep surveys at 850 mu m from Mauna Kea using the SCUBA camera on the JCMT appear to have discovered a substantial population of ultraluminous infrared galaxies (ULIGs: L-ir > 10(12)L (circle dot))(3) at high redshift (z similar to 1.-4). The cumulative space density of these sources (similar to 10(4) deg(-2) with S-850 > 1 mJy) is sufficient to account for nearly all of the extragalactic background light at submillimeter wavelengths. Current estimates of the redshift distribution suggest a peak in the comoving space density of SCUBA sources at z = 1 - 3, similar to what is observed for QSOs and radio galaxies. The luminosity density in the far-infrared/submillimeter exceeds that in the UV by factors of 3-10 over this redshift range, implying that as much as 80-90 % of the "activity" in galaxies at z less than or similar to 4 is hidden by dust. The SCUBA sources plausibly represent the primary epoch in the formation of spheroids and massive black holes triggered by major mergers of gas-rich disks. (C) 2000 COSPAR. Published by Elsevier Science Ltd.