MODELING OF THE SPECTRA OF BROAD GAMMA-RAY LINES IN ASTROPHYSICAL OBJECTS

We constructed a model and performed calculations of the spectra of ga mma-ray lines produced by interactions of accelerated nuclei with ther mal plasma in astrophysical objects with a high rate of energy generat ion. The model allows for the spatial nonuniformity of the distributio n of accelerated nuclei due to their diffusive propagation through a d ense medium with Coulomb losses. The Doppler-broadened spectra of broa d gamma-ray Lines were calculated with a proper allowance for the kine matics of two- and three-particle reactions. Substantial splitting of broad lines (the formation of narrow quasi-lines) is shown to occur fo r an isotropic distribution of emitting nuclei. This effect results fr om anisotropy of the angular distribution of emitted photons in the re st frame of the nucleus with the subsequent Doppler shift, The model w e propose can be used to interpret the observed gamma-ray spectra of O and B associations, compact accreting objects, and solar flares.