Huynh, M. T.Norris, R. P.Coppin, K. E. K.Emonts, B. H. C.Ivison, R. J.Seymour, N.Smail, IanSmolcic, V.Swinbank, A. M.Brandt, W. N.Chapman, S. C.Dannerbauer, H.De Breuck, C.Greve, T. R.Hodge, J. A.Karim, A.Knudsen, K. K.Menten, K. M.van der Werf, P. P.Walter, F.Weiss, A.2014-03-122014-03-122013-02-13Huynh, M. T., R. P. Norris, K. E. K. Coppin, B. H. C. Emonts, et al. 2013. "Physical Conditions of the Gas in an ALMA [CII]-identified Submillimetre Galaxy at z = 4.44." Monthly Notices of the Royal Astronomical Society: Letters, Volume 431(1); L88-L921745-3933http://hdl.handle.net/10222/45337http://dx.doi.org/10.1093/mnrasl/slt014We present CO(2-1) observations of the submillimetre galaxy ALESS65.1 performed with the Australia Telescope Compact Array at 42.3 GHz. A previous ALMA study of submillimetre galaxies in the Extended Chandra Deep Field South detected [CII] 157.74 micron emission from this galaxy at a redshift of z = 4.44. No CO(2-1) emission was detected but we derive a firm upper limit to the cold gas mass in ALESS65.1 of M_gas 4 SMGs being the likely progenitors of massive red-and-dead galaxies at z > 2. The ratio of the [CII], CO and far-infrared luminosities implies a strong far-ultraviolet field of G_0 > 10^3, as seen in Galactic star forming regions or local ULIRGs. The observed L_[CII]/L_FIR = 2.3 x 10^{-3} is high compared to local ULIRGs and, combined with L_[CII]/L_CO > 2700, it is consistent with ALESS65.1 either having an extended (several kpc) [CII] emitting region or lower than solar metallicity.article4311L88