An ALMA survey of the SCUBA-2 CLS UDS field: Physical properties of 707
  Sub-millimetre Galaxies
  We analyse the physical properties of a large, homogeneously selected sample
of ALMA-located sub-mm galaxies (SMGs). This survey, AS2UDS, identified 707
SMGs across the ~1 sq.deg. field, including ~17 per cent, which are undetected
at $K$>~25.7 mag. We interpret their ultraviolet-to-radio data using MAGPHYS
and determine a median redshift of z=2.61+-0.08 (1$\sigma$ range of z=1.8-3.4)
with just ~6 per cent at z>4. Our survey provides a sample of 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$_\odot$. We find no evolution in dust
temperature at a constant far-infrared luminosity across z~1.5-4. The gas mass
function of our sample increases to z~2-3 and then declines at z>3. The space
density and masses of SMGs suggest that almost all galaxies with
$M_\ast$>~3x10$^{11}$M$_\odot$ have passed through an SMG-like phase. 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
$M_h$~6x10$^{12}$M$_\odot$, thus SMGs may represent the highly efficient
collapse of gas-rich massive halos. We show that SMGs are broadly consistent
with simple homologous systems in the far-infrared, 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.
