Radio SNRs in the Magellanic Clouds as probes of shock microphysics
  A large number of supernova remnants (SNRs) in our Galaxy and galaxies nearby
have been resolved in various radio bands. This radio emission is thought to be
produced via synchrotron emission from electrons accelerated by the shock that
the supernova ejecta drives into the external medium. Here we consider the
sample of radio SNRs in the Magellanic Clouds. Given the size and radio flux of
a SNR, we seek to constrain the fraction of shocked fluid energy in non-thermal
electrons ($\epsilon_e$) and magnetic field ($\epsilon_B$), and find
$\epsilon_e \epsilon_B \sim 10^{-3}$. These estimates do not depend on the
largely uncertain values of the external density and the age of the SNR. We
develop a Monte Carlo scheme that reproduces the observed distribution of radio
fluxes and sizes of the population of radio SNRs in the Magellanic Clouds. This
simple model provides a framework that could potentially be applied to other
galaxies with complete radio SNRs samples.
