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Energy spectra of particles accelerated by the first-order Fermi mechanismare investigated at ultrarelativistic shock waves, outside the range of Lorentzfactors considered previously. For particle transport near the shock anumerical method involving small amplitude pitch-angle scattering is appliedfor flows with Lorentz factors $\gamma$ from 3 to 243. For large $\gamma$shocks a convergence of derived energy spectral indices up to the value$\sigma_\infty \approx 2.2$ is observed for all considered turbulenceamplitudes and magnetic field configurations. Recently the same index wasderived for $\gamma$-ray bursts by Waxman [Astrophys. J. Lett. 485, L5 (1997)].Comment: 4 pages, 6 figure

Energy Spectra of Cosmic Rays Accelerated at Ultrarelativistic Shock Waves