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Durham University

Department of Physics

Staff profile

Publication details for Professor Ian Smail

Huynh, M.T., Norris, R.P., Coppin, K.E.K., Emonts, B.H.C., Ivison, R.J., Seymour, N., Smail, I., Smol\v cić, 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. (2013). Physical conditions of the gas in an ALMA [C II]-identified submillimetre galaxy at z = 4.44. Monthly notices of the Royal Astronomical Society 431(1): L88-L92.

Author(s) from Durham


We present 12CO(2-1) observations of the submillimetre galaxy ALESS65.1 performed with the Australia Telescope Compact Array (ATCA) at 42.3 GHz. A previous Atacama Large Millimeter Array study of submillimetre galaxies (SMGs) in the Extended Chandra Deep Field South detected [C II] 157.74 μm emission from this galaxy at a redshift of z = 4.44. No 12CO(2-1) emission was detected but we derive a firm upper limit to the cold gas mass in ALESS65.1 of M_gas < 1.7 × 10^{10} M_{{⊙}}. The estimated gas depletion time-scale is <50 Myr, which is similar to other high-redshift SMGs, and consistent with z > 4 SMGs being the likely progenitors of massive red-and-dead galaxies at z > 2. The ratio of the [C II], 12CO and far-infrared luminosities implies a strong far-ultraviolet field of G0 ≳ 103, as seen in Galactic star-forming regions or local ultraluminous infrared galaxies (ULIRGs). The observed L_{[C II]}/L_FIR = 2.3 × 10^{-3} is high compared to local ULIRGs and, combined with L_{[C II]}/L_CO ≳ 2700, it is consistent with ALESS65.1 either having an extended (several kpc) [C II] emitting region or lower than solar metallicity.