Observations of Hyperluminous Infrared Galaxies with the Infrared Space   Observatory: Implications for the origin of their extreme luminosities
  We present 7-180micron photometry of a sample of hyperluminous infrared galaxies (HyLIGs) obtained with the photometer and camera mounted on the Infrared Space Observatory. We have used radiative transfer models of obscured starbursts and dusty torii to model their spectral energy distributions (SEDs). We find that F00235+1024, F14218+3845 and F15307+3252 require a combination of starburst and AGN components to explain their mid to far-infrared emission, while for TXS0052+471 a dust torus AGN model alone is sufficient. For F00235+1024 and F14218+3845 the starburst component is the predominant contributor whereas for F15307+3252 the dust torus component dominates. The implied star formation rates (SFR) for these three sources estimated from their infrared luminosities are $\dot{M}_{*,all} > 3000M_{\odot}yr^{-1}h_{50}^{-2}$ and are amongst the highest SFRs estimated to date. We also demonstrate that the well-known radio-FIR correlation extends into both higher radio and infrared power than previously investigated. The relation for HyLIGs has a mean q value of ~1.94. The results of this study imply that better sampling of the IR spectral energy distributions of HyLIgs may reveal that both AGN and starburst components are required to explain all the emission from the NIR to the sub-millimetre. 
Aprajita Verma, Michael Rowan-Robinson, Richard McMahon and Andreas   Efstathiou