Radio Emission Variability of Supernova Remnants and a Possible Explanation of the Phenomenon

The flux densities and current spectra of plerions and combined supernova remnants (SNRs): 3C58, 3C144, G11.2–0.3, G21.5–0.9, and 3C396 are determined on an artificial moon (AM) flux scale. The radio emission variability of the objects on different time scales is studied by multiple measurements using the RT-32 radio telescope at the Svetloe Observatory, Institute of Applied Astronomy, Russian Academy of Sciences and by mutual comparisons of the published measurement data, which have been brought to a common system using the AM flux scale. The radio emission from the SNRs displays both slow evolutionary variations and rapid ones, nonstationary in time. The rapid variability of the SNRs has features that are similar to those observed during solar flares. This fact may testify to the identity of the physical mechanisms underlying the rapid variability of the radio emission from plerions and from the Sun. Field line reconnections are considered as such a common mechanism.