Movies Corresponding to Figure 10 of "A Transition in Circumbinary Accretion Discs at a Binary Mass Ratio of 1:25", Published in MNRAS. On the arXiv

q=0.001

q=0.01

q=0.05

Movies From "Accretion into the Central Cavity of a Circumbinary Gas Disc"

Zoltan Haiman, Andrew MacFadyen and I are simulating accretion disks
around massive black hole binaries in the (non gravitational-wave
dominated) inspiral regime. In 2013 we published
a paper which explores how such disks respond to
circular binaries of different mass ratios, q = (Mass of
secondary)/(Mass of primary). In this study we are chiefly interested
in the mass accretion rate towards the holes. We find that three main
variability timescales appear in the simulated accretion rates as a
function of q. Two of these timescales (1x and 2x the binary orbital
period) are set strictly by the binary orbital parameters. A longer
variability period (~3-8x the binary orbital period) depends on disk
parameters. Knowledge of the two accretion timescales set by the
binary may aid in identifying binaries in galactic nuclei. If a binary
in the inspiral stage is identified in future surveys
(since writing
the future is now!), identification of such a third,
longer timescale could provide clues to the conditions present in a
putative disk surrounding the holes.

The movies below elaborate on Figure 3 of
the paper and can be played by clicking on the desired
density profile snapshot. Each depicts the inner 6 r/a of the
disk (inner 6% in radius of the simulated disk) where a is the
binary separation. The inner solid circle denotes the inner edge of
the simulation domain and is where we measure accretion rates. The
larger dashed circle is set at r = 2.08a to guide the eye. The
first two movies, from left to right, are for an equal mass (q=1.0)
binary with the first having a viscosity parameter of alpha=0.01 and
the second having a viscosity parameter of alpha=0.04. The subsequent
movies have mass ratios decreasing from left to right, top to bottom: q=0.5, q=0.25,
q=0.1, q=0.01; all with viscosity parameter alpha=0.01.