PPT Slide
Total energy release over life of Universe = 10 x 10 x 10 J ~ 10 J (1000 radio gals)
Energy density ~ 10 J m ...the order of the energy density required IF the value measured at Earth is universal
Quasars are another possible source of CR
- the radio galaxies must be replaced
Notes:
The total energy released over the 10 billion year lifetime of the Universe is 1000 (the number of galaxies) times their energy output (optimistically, 1e55J) times the number of times that the radio galaxies must be replaced to maintain a constant number of 1000 radio galaxies (which is 10,000). So the total energy released in 1e10 years is 1e62 J. In a volume of 1e75 m^3, this is an energy density of 1e-13 J/m^3.
This is comparable to the observed energy density of cosmic rays, if it can be assumed that the value measured at the Earth is universal.
Quasars are also sources of cosmic rays and are even more energetic than radio galaxies. Thus they add further support to an extragalactic origin of cosmic rays.