The SCUBA Half Degree Extragalactic Survey - IV. Radio-mm-FIR photometric redshifts

Itziar Aretxaga, David H. Hughes, Kristen Coppin, Angela M.J. Mortier, Jeff Wagg, James S. Dunlop, Edward L. Chapin, Stephen A. Eales, Enrique Gaztañaga, Mark Halpern, Rob J. Ivison, Eelco Van Kampen, Douglas Scott, Stephen Serjeant, Ian Smail, Thomas Babbedge, Andrew J. Benson, Scott Chapman, David L. Clements, Loretta DunneSimon Dye, Duncan Farrah, Matt J. Jarvis, Robert G. Mann, Alexandra Pope, Robert Priddey, Steve Rawlings, Marc Seigar, Laura Silva, Chris Simpson, Mattia Vaccari

Research output: Contribution to journalArticle

83 Scopus citations

Abstract

We present the redshift distribution of the Submillimetre Common-User Bolometer Array (SCUBA) Half Degree Survey (SHADES) galaxy population based on the rest-frame radio-mm-far-infrared (FIR) colours of 120 robustly detected 850 μm sources in the Lockman Hole East (LH) and Subaru XMM-Newton Deep Field (SXDF). The redshift distribution derived from the full spectral energy distribution (SED) information is shown to be narrower than that determined from the radio-sub-mm spectral index, as more photometric bands contribute to a higher redshift accuracy. The redshift distribution of sources derived from at least two photometric bands peaks at z ≈ 2.4 and has a near-Gaussian distribution, with 50 per cent (interquartile range) of sources at z = 1.8-3.1. We find a statistically significant difference between the measured redshift distributions in the two fields; the SXDF peaking at a slightly lower redshift (median z ≈ 2.2) than the LH (median z ≈ 2.7), which we attribute to the noise properties of the radio observations. We demonstrate, however, that there could also be field-to-field variations that are consistent with the measured differences in the redshift distributions and, hence, that the incomplete area observed by SHADES with SCUBA, despite being the largest sub-mm survey to date, may still be too small to fully characterize the bright sub-mm galaxy population. Finally, we present a brief comparison with the predicted, or assumed, redshift distributions of sub-mm galaxy formation and evolution models, and we derive the contribution of these SHADES sources and the general sub-mm galaxy population to the star formation rate density at different epochs.

Original languageEnglish (US)
Pages (from-to)1571-1588
Number of pages18
JournalMonthly Notices of the Royal Astronomical Society
Volume379
Issue number4
DOIs
StatePublished - Aug 2007

Keywords

  • Cosmology: miscellaneous
  • Galaxies: evolution
  • Infrared: galaxies
  • Submillimetre
  • Surveys

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    Aretxaga, I., Hughes, D. H., Coppin, K., Mortier, A. M. J., Wagg, J., Dunlop, J. S., Chapin, E. L., Eales, S. A., Gaztañaga, E., Halpern, M., Ivison, R. J., Van Kampen, E., Scott, D., Serjeant, S., Smail, I., Babbedge, T., Benson, A. J., Chapman, S., Clements, D. L., ... Vaccari, M. (2007). The SCUBA Half Degree Extragalactic Survey - IV. Radio-mm-FIR photometric redshifts. Monthly Notices of the Royal Astronomical Society, 379(4), 1571-1588. https://doi.org/10.1111/j.1365-2966.2007.12036.x