Search for X-ray evidence of cosmic ray acceleration in SNR shocks

The discovery using ASCA that the featureless X-ray spectrum from the shell of SN 1006 is produced by shock-accelerated TeV electrons, and is thus an indicator of cosmic ray acceleration, has sparked a search for X-ray spectr al evidence for cosmic ray acceleration in other remnants, as well as much theoretical work. Thus far evidence for cosmic ray acceleration, in the for m of synchrotron continuum components, has been found in several additional remnants, including Cas A, G347.5-0.5, and IC 443. The information provide d by both detections and non-detections of these components can be used to investigate the shock acceleration process. We review the latest results of the continuing search for X-ray indicators of cosmic ray acceleration in G alactic and Magellanic Cloud SNR's and what we have learned thus far from i t.