SPALLATION OF IRON IN BLACK-HOLE ACCRETION FLOWS

In the local Galactic interstellar medium there is approximate energy equipartition between cosmic rays, magnetic fields, and radiation. If this holds in the central regions of active galactic nuclei (AGNs), in particular Seyfert galaxies, then considerable nuclear spallation of Fe occurs, resulting in enhanced abundances of the sub-Fe elements Ti, V, Cr, and Mn. These elements produce a cluster of X-ray fluorescence lines at energies just below the 6.4 keV Fe K alpha line. It is sugge sted that the red wings on the Fe lines observed with ASCA from variou s Seyfert AGNs are due to the unresolved line emission from these elem ents. Future observations with more sensitive X-ray instruments should resolve these lines. The estimated gamma-ray emission from nuclear de -excitation and neutral pion production is calculated and found to be below the sensitivities of any current instruments. However, very lumi nous nearby Seyferts displaying Fe lines with red wings could have > 1 00 MeV continuum emissions detectable by future instruments such as th e Gamma-Ray Large Area Space Telescope.