University of Hertfordshire

From the same journal

From the same journal

By the same authors

  • U. Dudzevičiūtė
  • Ian Smail
  • A. M. Swinbank
  • S. M. Stach
  • O. Almaini
  • E. da Cunha
  • Fang Xia An
  • V. Arumugam
  • J. Birkin
  • A. W. Blain
  • S. C. Chapman
  • C. J. Conselice
  • J. S. Dunlop
  • D. Farrah
  • B. Gullberg
  • W. G. Hartley
  • J. A. Hodge
  • R. J. Ivison
  • D. T. Maltby
  • D. Scott
  • C. J. Simpson
  • F. Walter
  • J. L. Wardlow
  • A. Weiss
  • P. van der Werf
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Original languageUndefined/Unknown
JournalMonthly Notices of the Royal Astronomical Society
Journal publication date16 Oct 2019
Publication statusSubmitted - 16 Oct 2019

Abstract

We analyse the physical properties of a large, homogeneously selected sample of ALMA-located sub-mm galaxies (SMGs) detected in the SCUBA-2 CLS 850-$\mu$m map of the UKIDSS/UDS field. This survey, AS2UDS, identified 707 SMGs across the ~1 sq.deg. field, including ~17 per cent which are undetected in the optical/near-infrared to $K$>~25.7 mag. We interpret the UV-to-radio data using a physically motivated model, MAGPHYS and determine a median photometric redshift of z=2.61+-0.08, with a 68th percentile range of z=1.8-3.4 and just ~6 per cent at z>4. The redshift distribution is well fit by a model combining evolution of the gas fraction in halos with the growth of halo mass past a threshold of ~4x10$^{12}$M$_\odot$, thus SMGs may represent the highly efficient collapse of gas-rich massive halos. Our survey provides a sample of the most massive, dusty galaxies at z>~1, with median dust and stellar masses of $M_d$=(6.8+-0.3)x10$^{8}$M$_\odot$ (thus, gas masses of ~10$^{11}$M$_\odot$) and $M_\ast=$(1.26+-0.05)x10$^{11}$M$_\odot$. These galaxies have gas fractions of $f_{gas}=$0.41+-0.02 with depletion timescales of ~150Myr. The gas mass function evolution at high masses is consistent with constraints at lower masses from blind CO-surveys, with an increase to z~2-3 and then a decline at higher redshifts. The space density and masses of SMGs suggests that almost all galaxies with $M_\ast$>~2x10$^{11}$M$_\odot$ have passed through an SMG-like phase. We find no evolution in dust temperature at a constant far-infrared luminosity across z~1.5-4. We show that SMGs appear to behave as simple homologous systems in the far-infrared, having properties consistent with a centrally illuminated starburst. Our study provides strong support for an evolutionary link between the active, gas-rich SMG population at z>1 and the formation of massive, bulge-dominated galaxies across the history of the Universe.

ID: 17601636