QPOs from misaligned accretion discs

We present a physcially motivated model where quasi-periodic oscillations are driven by Lense-Thirring precession. Recent SPH simulations have shown that when the disc is inclined to the spin of the black hole, it can be ripped up into rings that precess effectively independently (e.g. Nixon et al. 2012, Nealon et al. 2015). These rings occur at ~5-20 gravitiational radii, where QPOs are expected to be sourced. The movie below shows an example of the type of simulation we are using to show that these rings are capable of producing frequencies that are comparable to observed QPOs.

The simulation above shows the same disc with density rendered on the left (in log scale) and the luminosity approximated from shock heating and compressive work on the right (in linear scale). We then sum this luminosity across the disc as a function of time to estimate a lightcurve from our simulations.