The Effect of Non-Thermal Protons on the High Energy Spectra of Black Hole Binaries

Abstract

In the inner regions of an accretion disk around a black hole, the presence of non-thermal protons would via p-p collisions produce electrons, positrons and $\gamma$-rays. For such a scenario, the steady state electron-positron distribution is computed taking into account Compton cooling, $e^{-} e^{+}$ pair production (due to $\gamma-\gamma$ interactions) and pair annihilation. The resultant spectra has a broad feature around $1 - 10$ MeV which may be tested with observations by INTEGRAL and GLAST. Using the available OSSE data for the black hole system, GRS 1915+115 we illustrate that an upper limit on the non-thermal proton fraction can be obtained, which may put constraints on the acceleration process active in this system.