Astrophysical objects with extreme energy release: observations and theory

Supernovae release extreme amounts of energy and produce major chemical elements in galaxies. They are extraordinary phenomena that give rise to the emission of neutrinos, gravitational waves, and broad spectra of electromagnetic radiation, and accelerate particles to ultra-relativistic energies. Observations of supernovae have led to the discovery of the accelerated expansion of the Universe and the introduction of the ‘dark energy’ concept. Recent observations and theoretical models have revealed diverse supernova-related phenomena, the diversity resulting from variations both in the energy release mechanisms and in the properties of circumstellar matter. Supernova remnants and, in particular, gamma-ray bursts originating from compact stellar remnants are among the main objects of space research programs all over the world. We review the results of supernova and gamma-ray burst observations, as well as physical models capable of explaining the acceleration of nonthermal particles to ultra-relativistic energies and the amplification of fluctuating magnetic fields in supernova shells. We also consider the prospects of testing these models via observations with orbital and ground-based telescopes.