The nature of the ultraluminous X-ray sources inside galaxies and their   relation to local QSOs
  It is suggested that many of the ultraluminous compact x-ray sources now being found in the main bodies of galaxies, particularly those that are active, like M82, NGC 3628 and others, are "local" QSOs, or BL Lac objects, with high intrinsic redshifts in the process of being ejected from those galaxies. Evidence in support of this hypothesis is summarized. 
G. Burbidge, E. M. Burbidge and H. Arp