Okay, so this may be a little bit of a trivial question, but I've read conflicting information and found myself confused as a result. I've read from several sources (wikipedia, books) that GRB's are the most luminous events known to occur in our universe. However, I've also read that Quasars are 'the most energetic and luminous objects in the known universe' (the physics book - Cllifford A. Pickover). So my question is, which is brighter? Nowhere that I've found on the net addresses the question. Some sites favour GRB's and others favour quasars, but nowhere compares them. Does anybody have any quantitive values? Thanks in advance!