Seminar by Stephen Reynolds, NC State
It is now generally accepted that the diffusive shock acceleration process is responsible for the acceleration of the relativistic-particle distributions observed in many Galactic contexts, with the strong shock waves from supernova remnants (SNRs) a prime candidate for acceleration sites. In particular, electrons make themselves apparent through synchrotron radiation at photon energies from radio through hard X-rays, and through inverse-Compton scattering in gamma rays. Synchrotron radiation dominates the X-ray spectrum of a handful of Galactic SNRs, and contributes substantially to that of several more. These objects allow detailed study of the electron populations and the local environments of their acceleration. I shall describe recent work on several of these objects with spatially and temporally resolved observations with the Chandra X-ray Observatory. Ongoing monitoring of the youngest Galactic SNR G1.9+0.3 with Chandra's sub-arcsecond spatial resolution has allowed the characterization of velocities and brightness changes, both increases and decreases, on length scales of a small fraction of the remnant radius. These results and others pose significant problems for theoretical modeling of electron acceleration.
Host: Kaya Mori