Balloon-borne Measurements of the SN 1987A Hard X-Ray Continuum

SN 1987A hard X-ray continuum spectra obtained on 1987 October 29, 1988 April 9-10, and 1988 November 11 from balloon-flight measurements are presented. The spectra, spanning the energy range from 25 keV to 300 keV, have been analyzed using a detector response matrix inversion technique that converts the spectra from counts s^-1^ cm^2^ keV to photons s^-1^ cm^2^ keV allowing direct comparison with theoretical models. The results indicate that the bulk of the ^56^Co is mixed moderately through the inner regions of the supernova envelope but they do not preclude the mixing of a small amount of the ^56^Co farther out into the envelope necessary to account for the observed ^56^Co line fluxes. The effect of the ratio ^57^Co to ^56^Co on the 1988 November 11 continuum spectrum is discussed.