The SCUBA-2 Cosmology Legacy Survey: the submillimetre properties of Lyman-break galaxies at z=3-5

K. E. K. Coppin*, J. E. Geach, O. Almaini, V. Arumugam, J. S. Dunlop, W. G. Hartley, R. J. Ivison, C. J. Simpson, D. J. B. Smith, A. M. Swinbank, A. W. Blain, M. Bremer, C. Conselice, C. M. Harrison, Alice Mortlock, S. C. Chapman, L. J. M. Davies, D. Farrah, A. Gibb, T. JennessA. Karim, K. K. Knudsen, E. Ibar, M. J. Michalowski, J. A. Peacock, D. Rigopoulou, I. Robson, D. Scott, J. Stevens, P. P. van der Werf, Nathan Bourne

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

We present detections at 850 mu m of the Lyman-break galaxy (LBG) population at z approximate to 3, 4, and 5 using data from the Submillimetre Common User Bolometer Array 2 Cosmology Legacy Survey in the United Kingdom Infrared Deep Sky Survey 'Ultra Deep Survey' field. We employ stacking to probe beneath the survey limit, measuring the average 850 mu m flux density of LBGs at z approximate to 3, 4, and 5 with typical ultraviolet luminosities of L-1700 approximate to 10(29) erg s(-1) Hz(-1). We measure 850 mu m flux densities of (0.25 +/- 0.03), (0.41 +/- 0.06), and (0.88 +/- 0.23) mJy, respectively, finding that they contribute at most 20 per cent to the cosmic far-infrared (IR) background at 850 mu m. Fitting an appropriate range of spectral energy distributions to the z similar to 3, 4, and 5 LBG stacked 24-850 mu m fluxes, we derive IR luminosities of L8-1000 (mu m) approximate to 3.2, 5.5, and 11.0 x 10(11) L-circle dot [and star formation rates (SFRs) of approximate to 50-200M(circle dot) yr(-1)], respectively. We find that the evolution in the IR luminosity density of LBGs is broadly consistent with model predictions for the expected contribution of luminous-to-ultraluminous IR galaxies at these epochs. We observe a positive correlation between stellar mass and IR luminosity and confirm that, for a fixed mass, the reddest LBGs (UV slope beta -> 0) are redder due to dust extinction, with SFR (IR)/SFR (UV) increasing by about an order of magnitude over -2 <beta <0 with SFR (IR)/SFR (UV) similar to 20 for the reddest LBGs. Furthermore, the most massive LBGs tend to have higher obscured-to-unobscured ratios, hinting at a variation in the obscuration properties across the mass range.

Original languageEnglish
Pages (from-to)1293-1304
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Volume446
Issue number2
DOIs
Publication statusPublished - 11 Jan 2015

Keywords

  • galaxies: evolution
  • galaxies: formation
  • galaxies: high-redshift
  • galaxies: star formation
  • submillimetre: galaxies
  • ultraviolet: galaxies
  • STAR-FORMING GALAXIES
  • DEEP FIELD-SOUTH
  • SIMILAR-TO 3
  • ULTRAVIOLET-SELECTED GALAXIES
  • HIGH-REDSHIFT
  • LUMINOSITY FUNCTION
  • STELLAR MASSES
  • EXTRAGALACTIC SURVEY
  • NUMBER COUNTS
  • DUST EMISSION

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