Ian Smail

TL;DR: The final version published in MNRAS August 2007 included significant revisions including significant revisions to the original version April 2006.

Abstract: We have obtained spectroscopic redshifts using the Keck I telescope for a sample of 73 submillimeter galaxies (SMGs), with a median 850 μm flux density of 5.7 mJy, for which precise positions are available through their faint radio emission. The galaxies lie at redshifts out to z = 3.6, with a median redshift of 2.2 and an interquartile range z = 1.7-2.8. Modeling a purely submillimeter flux-limited sample, based on the expected selection function for our radio-identified sample, suggests a median redshift of 2.3, with a redshift distribution remarkably similar to the optically and radio-selected quasars. The observed redshift distributions are similar for the active galactic nucleus (AGN) and starburst subsamples. The median RAB is 24.6 for the sample. However, the dust-corrected ultraviolet (UV) luminosities of the galaxies rarely hint at the huge bolometric luminosities indicated by their radio/submillimeter emission, with the effect that the true luminosity can be underestimated by a median factor of ~120 for SMGs with pure starburst spectra. Radio and submillimeter observations are thus essential to select the most luminous high-redshift galaxies. The 850 μm, radio, and redshift data are used to estimate the dust temperatures and characterize photometric redshifts. Using 450 μm measurements for a subset of our sample, we confirm that a median dust temperature of Td = 36 ± 7 K, derived on the assumption that the local far-infrared (FIR)-radio correlation applies at high redshift, is reasonable. Individual 450 μm detections are consistent with the local radio-FIR relation holding at z ~ 2. This median Td is lower than that estimated for similarly luminous IRAS 60 μm galaxies locally. We demonstrate that dust temperature variations make it impossible to estimate redshifts for individual SGMs to better than Δz 1 using simple long-wavelength photometric methods. We calculate total infrared and bolometric luminosities (the median infrared luminosity estimated from the radio is 8.5 × 1012 L☉), construct a luminosity function, and quantify the strong evolution of the submillimeter population across z = 0.5-3.5 relative to local IRAS galaxies. We use the bolometric luminosities and UV-spectral classifications to determine a lower limit to the AGN content of the population and measure directly the varying the contribution of highly obscured, luminous galaxies to the luminosity density history of the universe for the first time. We conclude that bright submillimeter galaxies contribute a comparable star formation density to Lyman break galaxies at z = 2-3, and including galaxies below our submillimeter flux limit, this population may be the dominant site of massive star formation at this epoch. The rapid evolution of SMGs and QSO populations contrasts with that seen in bolometrically lower luminosity galaxy samples selected in the rest-frame UV and suggests a close link between SMGs and the formation and evolution of the galactic halos that host QSOs.

TL;DR: In this paper, the authors presented the first results of a submillimeter survey of distant clusters using the new Submillimeter Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope.

TL;DR: In this paper, the authors used traditional morphological classifications of galaxies in 10 intermediate-redshift (z similar to 0.5) clusters observed with WFPC2 on the Hubble Space Telescope, and derived relations between morphology and local galaxy density similar to that found by Dressier for low-Redshift clusters.

TL;DR: The zCOSMOS-bright survey as discussed by the authors is a large-redshift survey that is being undertaken in the CosMOS field using 600 hr of observation with the VIMOS spectrograph on the 8 m VLT.