Particle acceleration in relativistic outflows
  In this review we confront the current theoretical understanding of particle acceleration at relativistic outflows with recent observational results on various source classes thought to involve such outflows, e.g. gamma-ray bursts, active galactic nuclei, and pulsar wind nebulae. We highlight the possible contributions of these sources to ultra-high-energy cosmic rays. 
Andrei Bykov and Neil Gehrels and Henric Krawczynski and Martin   Lemoine and Guy Pelletier and Martin Pohl
astro-ph.HE