Simulations of flux variability of oscillating accretion fluid tori   around Kerr black holes
  High frequency quasi-periodic oscillations (HF QPOs) are observed in the X-ray power-density spectra (PDS) of several microquasars and low mass X-ray binaries. Many proposed QPO models are based on oscillations of accretion toroidal fluid structures orbiting in the vicinity of a compact object. We study oscillating accretion tori orbiting in the vicinity of a Kerr black hole. We demonstrate that significant variation of the observed flux can be caused by the combination of radial and vertical oscillation modes of a slender, polytropic, perfect fluid, non-self-graviting torus with constant specific angular momentum. We investigate two combinations of the oscillating modes corresponding to the direct resonance QPO model and the modified relativistic precession QPO model. 
Pavel Bakala, Kate\v{r}ina Goluchov\'a, Eva \v{S}r\'amkov\'a, Andrea   Kotrlov\'a, Gabriel T\"or\"ok, Frederic H. Vincent an...
astro-ph.HE