srcut: synchrotron spectrum, cutoff power law

srcut describes the synchrotron spectrum from an exponentially cut off power-law distribution of electrons in a homogeneous magnetic field. This spectrum is itself a power-law, rolling off more slowly than exponential in photon energies. Though more realistic than a power-law, it is highly oversimplified,  but does give the maximally curved physically plausible spectrum and can be used to set limits on maximum accelerated-electron energies even in remnants whose X-rays are thermal. See Reynolds, S.P. & Keohane, J.W.  1999, ApJ, 525, 368 and Reynolds, S.P., 1998 ApJ 493, 357. Note that the radio spectral index and flux can be obtained from Green's Catalogue at   http://www.mrao.cam.ac.uk/surveys/snrs  for galactic SNRs.

 

par1	alpha: radio spectral index
par2	break Hz: approximately the frequency at which the flux has dropped by a factor of 10 from a straight power law.
norm	1 GHz flux (Jy)