Slide 32 of 48
Notes:
So to calculate the spectrum in the regime where the synchrotron emission would exceed the Rayleigh-Jeans flux, we assume that it can be described as a thermal source and replace the mean energy per particle (~kT) with the value of E at the peak frequency nu_max. Then to calculate the flux, the intensity has to be multiplied by the angle subtended by the source at the Earth, Omega.
Note that the resulting emission will not be blackbody though, because the electrons do not have a thermal distribution.
