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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)