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The evolution of submillimetre galaxies: two populations and a redshift cut-off

J. V. Wall·Alexandra Pope·D. S. Scott
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Abstract

We explore the epoch dependence of number density and star-formation rate for submillimetre galaxies (SMGs) found at 850 um. The study uses a sample of 38 SMG in the GOODS-N field, for which cross-waveband identifications have been obtained for 35/38 members together with redshift measurements or estimates. A maximum-likelihood analysis is employed, along with the `single-source-survey' technique. We find a diminution in both space density and star formation rate at z > 3, closely mimicking the redshift cut-offs found for QSOs selected in different wavebands. The diminution in redshift is particularly marked, at a significance level too small to measure. The data further suggest, at a significance level of about 0.001, that two separately-evolving populations may be present, with distinct luminosity functions. These results parallel the different evolutionary behaviours of LIRGs and ULIRGs, and represent another manifestation of `cosmic down-sizing', suggesting that differential evolution extends to the most extreme star-forming galaxies.

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J. V. Wall, Alexandra Pope, D. S. Scott. 2007-12-09. The evolution of submillimetre galaxies: two populations and a redshift cut-off. https://doi.org/10.1111/j.1365-2966.2007.12547.x

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