Particle Acceleration in the Remnants of Supernova Explosions

Daniel Castro

Center for Astrophysics - Harvard & Smithsonian

Tuesday, Sep 14, 2021

Abstract

Supernova remnants (SNRs) and pulsar wind nebulae (PWNe) have great impact on the energy density and evolution of the galaxies where supernovae (SNe) take place. SNR shocks interact with the surrounding medium, compressing and heating it, as well as accelerating particles to cosmic ray (CR) energies. Most of the energy carried away by CRs is available to drive outflows in the interstellar medium (ISM), and thus they are a significant factor in galactic formation and evolution. The study of SNRs allows for understanding issues of great relevance in astrophysics, like stellar collapse and particle acceleration mechanisms. Furthermore, some core-collapse SNe leave behind rapidly spinning neutron stars (pulsars) as compact remnants of the progenitor systems, many of which create relativistic particle nebualae. PWNe studies provide us with information on particle acceleration mechanisms at relativistic shocks, on the evolution of the pulsar spin down and, at later phases, on the ambient interstellar gas. While the basic understanding of SNRs and PWNe has been developed, we still lack detailed knowledge about the characteristics of the relativistic particle populations in these systems, and particularly how efficient are SNR shocks at accelerating CRs. Moreover, the evolution of SNRs and PWNe under different conditions and how that is reflected in their high-energy γ-ray emission is yet to be well determined. To address these outstanding questions, we have undertaken an ambitious program of observational studies of SNRs and PWNe in the gamma-ray and X-ray bands, in combination with multi-wavelength observations and modeling. I will discuss our latest results in this presentation.