ENHANCED COSMIC-RAY ACCELERATION RATES IN HIGHLY INCLINED ASTROPHYSICAL SHOCKS

The theory of cosmic-ray acceleration by subluminal MHD astrophysical shocks according to the test particle approximation is extended to hig hly oblique shocks where flow speeds which appear nonrelativistic in t he shock rest frame appear on transformation to the de Hoffmann-Teller or E=0 frame to have upstream flow speeds approaching c. Monte Carlo simulation shows that relative to the predictions of diffusion theory, as the upstream E=0 frame velocity approaches c, flatter spectra and faster acceleration rates occur. These spectral and acceleration time changes are similar to those found for relativistic, parallel MHD shoc ks and may affect all nonthermal active galactic nuclei emission from relativistic electrons. Also there is an additional means of increasin g the upper limit of the cosmic-ray spectrum expected from active gala ctic nuclei, although the approximation used may not accurately reprod uce the spectral shape.