Superluminous accretion discs

Abstract

In this paper I compute upper limits for the total luminosities and collimation of radiation from thick, radiation supported accretion discs around black holes. I present numerical results obtained for the ‘extreme’ discs with $$r_\text{out}=10^3GM_\text{BH}/c^2$$, the angular momentum of the black hole being $$J_\text{BH}=0.998\enspace GM_\text{BH}/c$$. The high luminosity (L ∼ 8.5 L_Edd) and substantial collimation of radiation found for these discs indicate that such discs can explain both the high luminosities of quasars and similar objects and may produce some of the observed beams and jets.