Antonis Manousakis Bhupendra Mishra (Nicolaus Copernicus Astronomical Center Warsaw Poland) Frederic Vincent (Observatoire de Paris)
We simulate a purely hydrodynamical torus with constant specific angular momentum around a Schwarzschild black hole. The goal is to search for quasi-periodic oscillations (QPOs) of the torus. Initial torus setup is subjected to radial, vertical and a diagonal (combination of radial and vertical) velocity perturbations. The hydrodynamical simulations are performed using the general relativistic magnetohydrodynamics code Cosmos++ and ray-traced using the GYOTO code. We found that exciting radial perturbations also trigger a plus mode, while vertical perturbations trigger an X-mode. The diagonal perturbation gives just a combination of radial and vertical perturbation. Existing radially perturbed hydrodynamic simulations are in full agreement with our findings. The behavior of QPOs in slender torus mimics those of non-slender torus. This confirms that in actual astrophysical accretion disks, no matter the model (thin, slim, thick), the QPOs will always be detected.
Bhupendra Mishra (Nicolaus Copernicus Astronomical Center Warsaw Poland)