Probing Shock Properties with Non-thermal X-ray Filaments in Cas A

Thin non-thermal X-ray filaments are often seen in young supernova remnants. We used data from the 1 Ms Chandra observation of Cassiopeia A to study spectral properties of some of the filaments in this remnant. For all the cases that we examined, the X-ray spectrum across the filaments hardens, at about 10% level, going outward, while observed filament widths depend only weakly on the photon energy. Using a model that includes radiative cooling, advection and diffusion of accelerated particles behind the shock, we estimated the magnetic field, turbulence level and shock obliquity.