There are many powerful astronomical objects in far-away region of the Universe such as Quasars. 3C270 shown below is one of those powerhouse. The core of this Quasar perhaps contains a supermassive black hole to power two jets of matter that spew from its center at high speed. Such jets may send out superenegetic neutrinos.

The superhigh energy cosmic neutrino beams emitted from the far-away powerhouse barely interact with the 3k photons avoiding the energy loss by the GZK mechanism, but might later collide with the relic neutrinos to initiate the neutrino cascades. The secondary particles initiated in the local neighborhood by the relic neutrinos possibely clustered forming the Hot Dark Matter constitute a bulk of the most energetic particles in the Universe.