%0 Journal Article
%T Herschel-ATLAS: a binary HyLIRG pinpointing a cluster of starbursting proto-ellipticals
%A R. J. Ivison
%A A. M. Swinbank
%A Ian Smail
%A A. I. Harris
%A R. S. Bussmann
%A A. Cooray
%A P. Cox
%A Hai Fu
%A A. Kovacs
%A M. Krips
%A D. Narayanan
%A M. Negrello
%A R. Neri
%A J. Penarrubia
%A J. Richard
%A D. A. Riechers
%A K. Rowlands
%A J. G. Staguhn
%A T. A. Targett
%A S. Amber
%A A. J. Baker
%A N. Bourne
%A F. Bertoldi
%A M. Bremer
%A J. A. Calanog
%A D. L. Clements
%A H. Dannerbauer
%A A. Dariush
%A G. De Zotti
%A L. Dunne
%A S. A. Eales
%A D. Farrah
%A S. Fleuren
%A A. Franceschini
%A J. E. Geach
%A R. D. George
%A J. C. Helly
%A R. Hopwood
%A E. Ibar
%A M. J. Jarvis
%A J. -P. Kneib
%A S. Maddox
%A A. Omont
%A D. Scott
%A S. Serjeant
%A M. W. L. Smith
%A M. A. Thompson
%A E. Valiante
%A I. Valtchanov
%A J. Vieira
%A P. van der Werf
%J Physics
%D 2013
%I arXiv
%R 10.1088/0004-637X/772/2/137
%X Panchromatic observations of the best candidate HyLIRG from the widest Herschel extragalactic imaging survey have led to the discovery of at least four intrinsically luminous z=2.41 galaxies across a ~100-kpc region - a cluster of starbursting proto-ellipticals. Via sub-arcsecond interferometric imaging we have measured accurate gas and star-formation surface densities. The two brightest galaxies span ~3 kpc FWHM in submm/radio continuum and CO J=4-3, and double that in CO J=1-0. The broad CO line is due partly to the multitude of constituent galaxies and partly to large rotational velocities in two counter-rotating gas disks -- a scenario predicted to lead to the most intense starbursts, which will therefore come in pairs. The disks have M(dyn) of several x 10^11 Msun, and gas fractions of ~40%. Velocity dispersions are modest so the disks are unstable, potentially on scales commensurate with their radii: these galaxies are undergoing extreme bursts of star formation, not confined to their nuclei, at close to the Eddington limit. Their specific star-formation rates place them ~>5x above the main sequence, which supposedly comprises large gas disks like these. Their high star-formation efficiencies are difficult to reconcile with a simple volumetric star-formation law. N-body and dark matter simulations suggest this system is the progenitor of a B(inary)-type ~10^14.6-Msun cluster.
%U http://arxiv.org/abs/1302.4436v2