Hyperluminous IRAS galaxies: solving the AGN/starburst mystery with XMM

There is still substantial debate over whether luminous infrared galaxies arepowered primarily by AGN or starformation. Although both processes are clearlyinvolved, and may be intimately related, the heavy obscuration in these sourcesmakes disentangling the components very difficult. Hard Xrays can penetratethis obscuration and reveal the hidden AGN, if present. With sufficiantlysensitive observations, it should even be possible to detect the Xray emissionexpected from the starformation processes, even if there is no accretingsupermassive black hole. XMM observations therefore have the potential solvethis longstanding mystery. Here we propose to observe 8 hyperluminous infraredgalaxiues the most extreme examples which form part of an unbiased sample. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]