Open AccessThe evolution of submillimetre galaxies: two populations and a redshift cut‐off
Author(s) -
Wall J. V.,
Pope Alexandra,
Scott Douglas
Publication year - 2008
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2007.12547.x
Subject(s) - physics , astrophysics , qsos , galaxy , redshift , luminous infrared galaxy , astronomy , star formation , cosmic variance , luminosity , cosmic cancer database , redshift survey , galaxy formation and evolution , stellar mass
We explore the epoch dependence of number density and star formation rate for submillimetre galaxies (SMGs) found at 850 μm. The study uses a sample of 38 SMG in the Great Observatories Origins Deep Survey (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 quasi‐stellar objects (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 Luminous Infrared Galaxies and Ultra‐Luminous Infrared Galaxies, and represent another manifestation of ‘cosmic down‐sizing’, suggesting that differential evolution extends to the most extreme star‐forming galaxies.