CCPP Brown Bag
A New Way To Grow Black Holes
We still do not know the details of the mechanism by which accretion disks accrete. The most common explanation is a turbulent viscosity caused by the magnetorotational instability. I will discuss new simulations we have performed in the context of accretion onto binary black holes that provide an alternate mechanism: spiral shock waves excited by the tidal gravitational field. These spiral shocks propagate through the entire disk, heating the gas and driving it into the black hole with surprising efficiency. This effect works in the absence of magnetic fields, and may be relevant to a wide variety of disk systems.