SIMBAD references

When applied to the blast wave formed by the explosion of a massive star as a supernova (SN), the theory of diffusive particle acceleration at shock fronts predicts a very high energy density in cosmic rays. Almost immediately after particles begin to be injected into the process, the cosmic ray pressure rises until comparable to the ram-pressure encountered by the shock front. Those supernovae which are observed in the radio band i.e., radio supernovae (RSNe), provide direct evidence of particle acceleration in the form of synchrotron emitting electrons. Furthermore, these objects are particularly interesting, since they are usually surrounded by a relatively dense confining medium. The acceleration of cosmic rays can then lead to the production of very high energy (VHE) gamma-rays which arise from collisions between energetic particles and target nuclei. We estimate the cosmic ray energy density assuming a fraction {PHI}≤1 of the energy available at the shock front is converted into cosmic rays. Combining this with the parameters describing the environment of the SN progenitor, as deduced from observations, and from more detailed modelling, we compute the flux at Earth F(>1TeV) of photons of energy above 1TeV. For the relatively weak but nearby supernova SN1987A we predict F(>1TeV)=2x10^–13photons/s/cm⁺² before the shock front encounters the ring of dense matter seen by the Hubble Space Telescope. Subsequently, the flux is expected to rise further. The medium around SN1993J in M81 is thought to have a density profile ρ{prop. to}r^–3/2, (with r the distance from the point of explosion) for which we predict a roughly constant flux of F(>1TeV)=2x10^–12photons/s/cm⁺². Once the shock emerges into the region where iρ{prop. to}r^–2, which is expected at larger distances, the flux should decrease in proportion to t^–1. This object thus presents an interesting target for observation by telescopes which detect the Cerenkov light emined by the air showers from VHE photons. A detection would provide observational confirmation of cosmic ray acceleration in supernovae.