Accretion disks around magnetically charged black holes in string theory with an Euler-Heisenberg correction

Abstract

A relativistic model of geometrically thin and optically thick accretion disks is worked out for a class of magnetically charged black holes, which are solutions to the Einstein-Maxwell-dilaton theory with a dilaton-coupled Euler-Heisenberg correction. Constraints on black hole parameters are derived from the subextremality condition and energy conditions. The Keplerian orbits, the time-averaged energy flux, the local temperature, the specific luminosity, and the conversion efficiency of accreting mass into radiation are obtained and compared with Schwarzschild and Gibbons-Maeda-Garfinkle-Horowitz-Strominger black holes.