What powers hyperluminous infrared galaxies at z ∼ 1–2?

We investigate what powers hyperluminous infrared galaxies (HyLIRGs; |L_{\rm IR, 8-1000\,\mu m}>10^{13} L⊙) at z ∼ 1–2, by examining the behaviour of the infrared luminosity function of active galactic nuclei (AGN) in relation to the infrared galaxy luminosity function. The former corresponds to emission from AGN-heated dust only, whereas the latter includes emission from dust heated by stars and AGN. Our results show that the two luminosity...