Small-scale structure of non-thermal X-rays in historical SNRs

The shock fronts of supernova remnants (SNRs) are the most probable acceleration sites of high energy electrons (up to ∼100 TeV) with diffusive shock acceleration (DSA). However, the evolution of the acceleration in SNRs is still unclear. Using the Chandra archival data, we resolve the spatial structure of the shocked region of five historical SNRs (Cas A, Kepler, Tycho, SN 1006, and RCW 86) in non-thermal X-rays. The non-thermal emission concentrates on very thin and filamentary regions (“filaments”) in all SNRs, as already reported in the SN 1006 case. We also report on the time evolution of the scale length of the filaments and roll-off frequency of their spectra.