Radiation Spectra of Advection Dominated Accretion Flows around Kerr   Black Holes
  We study the formation of the spectra in advection dominated accretion flows (ADAFs) around Kerr black holes. We use a Monte Carlo approach and fully general relativistic treatment to follow the paths of individual photons and model their scattering with mildly relativistic, thermal electrons of the two temperature plasma present in the flow. We study the influence of the accretion rate, black hole mass, black hole angular momentum, and the strength of the small scale magnetic field present in the plasma on the resulting spectra. The impact of the black hole angular momentum on the spectra is present and can be distinguished from the influence of changes in other parameters. This property of the models should be taken into account when modeling the individual sources and the population of inefficiently accreting black holes in the Universe. 
A. Kurpiewski, M. Jaroszynski (Warsaw University Observatory)