Marko

Supernova remnants (SNRs) are believed to accelerate particles up to high energies, at least
reaching a few PeV, through the mechanism of diffusive shock acceleration (DSA). Detection of
synchrotron radio emission from cosmic ray (CR) electrons supports this picture.

We use two-dimensional hydrodynamic simulations of SNRs, evolving through a homogeneous
ambient medium, coupled with particle acceleration and magnetic field amplification at
non-relativistic shocks to derive the total radio emission. We assume that dynamical reaction
of the accelerated particles on the plasmas involved in the shock formation may not be
negligible as previously assumed in test particle methods and the CR spectrum is affected in a
substantial way. We coupled a simple Blasi’s semi-analytical model that deals with these
non-linear effects in a quantitative way and changes hydrodynamics by means of an effective
adiabatic index. Bell’s cosmic-ray non-resonant streaming instability is considered to be
responsible for the amplification of precursor magnetic field.

We obtained the radio synchrotron surface brightness increasing with time in the free
expansion phase, achieving its peak value at the beginning of the Sedov phase, and then
decreasing during later phases. The dependence of the radio surface brightness on the
diameter (time), has been calculated for different values of the interstellar medium
density, supernova explosion energy, injection efficiency and different initial ejecta clumping,
covering the region of the existing experimental points.

Obtained evolutionary tracks will be of the utmost importance for the future observations
carried out from a powerful radio telescopes like ALMA and SKA. This method can provide
distances to SNRs but also important information and constraints on the evolutionary stage of
SNRs, their CR production efficiency as well as the parameters of the surrounding medium.