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R. K. Williams (University of Florida and Bennett College)
Monte Carlo computer model simulations show that Penrose Compton scattering (PCS) near the event horizon and Penrose pair production (PPP) at or near the photon orbit, in the ergosphere of a supermassive (M=108 M\odot) rotating black hole, can generate the necessary energy-momentum spectra to explain the origin of the mysterious fluxes of ultrarelativistic electrons, inferred from observations to emerge from the cores of Quasars 3C 279 and 3C 273, and other active galactic nuclei (AGNs). Particles from an accretion disk surrounding the black hole fall into the ergosphere and scatter off particles that are in trapped or bound unstable orbits. The Penrose mechanism allows rotational energy of a Kerr black hole, and energy-momentum produced by its strong gravitational field, to be extracted by scattered particles escaping from the ergosphere to infinity (i.e., large distances from the black hole). The results of these model calculations show that the Penrose mechanism is capable of producing the observed high energy particles (~~GeV) emitted by quasars and other AGNs. This mechanism can extract hard X-ray/\ga-ray photons from PCS of initially infalling low energy UV/soft X-ray photons by target orbiting electrons in the ergosphere. The PPP (\ga\ga\longrightarrow e-e+) allows the escape of relativistic e- e+ pairs---produced by infalling low energy photons interacting with highly blueshifted target photons at the photon orbit. These e- e+ pairs emerge with maximum Lorentz factor ~104, which are consistent with relativistic beaming models used to explain the high energy spectra of so-called blazars, such as 3C~279 and 3C~273. Moreover, and importantly, the emission of scattered particles by this mechanism naturally produces relativistic jets collimated about the polar axis, and in most cases one-sided or asymmetrical, agreeing with observations of AGNs. In these fully relativistic calculations, the energy-momentum four vectors (or four-momenta) of the scattered particles are obtained. Based on the consistency of the four-momenta of the scattered Penrose particles with observations of quasars and other objects we observe to be powered by black holes, i.e., the high energies and luminosities, asymmetrical and collimated jets, it appears that geodesic treatment of many individual particles is sufficient to describe the flow of the particles, at least very close to the event horizon. This work was supported in part by at a grant from the American Astronomical Society.
The author(s) of this abstract have provided an email address for comments about the abstract: revak@astro.ufl.edu