  It is shown that the radio and gamma-ray emission observed from newly-found
"GeV-bright" supernova remnants (SNRs) can be explained by a model, in which a
shocked cloud and shock-accelerated cosmic rays (CRs) frozen in it are
simultaneously compressed by the supernova blastwave as a result of formation
of a radiative cloud shock. Simple reacceleration of pre-existing CRs is
generally sufficient to power the observed gamma-ray emission through the
decays of neutral pions produced in hadronic interactions between high-energy
protons (nuclei) and gas in the compressed-cloud layer. This model provides a
natural account of the observed synchrotron radiation in SNRs W51C, W44 and IC
443 with flat radio spectral index, which can be ascribed to a combination of
secondary and reaccelerated electrons and positrons.
