Quasi-periodic oscillations from relativistic ray-traced hydrodynamical tori

We simulate an oscillating polytropic torus with constant specific angular momentum around a Schwarzschild black hole. The goal is to search for quasi-periodic oscillations in the light curve of the torus. The torus is subjected to an initial radial, vertical or diagonal (combination of radial and vertical) velocity perturbation. The hydrodynamical simulations are performed using the general relativistic magnetohydrodynamics code cosmos++ and ray traced using the general relativistic ray-tracing code gyoto. We found that a horizontal velocity perturbation triggers the radial and plus modes, whereas a vertical velocity perturbation triggers the vertical and X modes. The diagonal perturbation gives a combination of the modes triggered in the radial and vertical cases. The breathing mode is excited in all cases. We find that the radial eigenmode frequency is independent of the equation of state used. We conclude that the radial and plus modes we find in our simulations are identical to f and o1 modes reported in Rezolla et al.