%0 Journal Article
%T The evolutionary connection between QSOs and SMGs: molecular gas in far-infrared luminous QSOs at z ~ 2.5
%A J. M. Simpson
%A Ian Smail
%A A. M. Swinbank
%A D. M. Alexander
%A R. Auld
%A M. Baes
%A D. G. Bonfield
%A D. L. Clements
%A A. Cooray
%A K. E. K. Coppin
%A A. L. R. Danielson
%A A. Dariush
%A L. Dunne
%A G. de Zotti
%A C. M. Harrison
%A R. Hopwood
%A C. Hoyos
%A E. Ibar
%A R. J. Ivison
%A M. J. Jarvis
%A A. Lapi
%A S. J. Maddox
%A M. J. Page
%A D. A. Riechers
%A E. Valiante
%A P. P. van der Werf
%J Physics
%D 2012
%I arXiv
%R 10.1111/j.1365-2966.2012.21941.x
%X We present IRAM Plateau de Bure Interferometer observations of the 12CO(3-2) emission from two far-infrared luminous QSOs at z ~ 2.5 selected from the Herschel-ATLAS survey. These far-infrared bright QSOs were selected to have supermassive black holes (SMBHs) with masses similar to those thought to reside in sub-millimetre galaxies (SMGs) at z ~ 2.5; making them ideal candidates as systems in transition from an ultraluminous infrared galaxy phase to a sub-mm faint, unobscured, QSO. We detect 12CO(3-2) emission from both QSOs and we compare their baryonic, dynamical and SMBH masses to those of SMGs at the same epoch. We find that these far-infrared bright QSOs have similar dynamical but lower gas masses than SMGs. In particular we find that far-infrared bright QSOs have ~50+-23% less warm/dense gas than SMGs, which combined with previous results showing the QSOs lack the extended, cool reservoir of gas seen in SMGs, suggests that they are at a different evolutionary stage. This is consistent with the hypothesis that far-infrared bright QSOs represent a short (~1Myr) but ubiquitous phase in the transformation of dust obscured, gas-rich, starburst-dominated SMGs into unobscured, gas-poor, QSOs.
%U http://arxiv.org/abs/1206.4692v1