Accretion Disk Parameters Determined from the Great 2015 Flare of OJ 287

In the binary black hole model of OJ 287 the secondary black hole orbits a much more massive primary, and impacts on the primary accretion disk at predictable times. We update the parameters of the disk, the viscosity \alphaand the mass accretion rate \dot m We find \alpha=0.26 \pm 0.1and \dot m = 0.08 \pm 0.04in Eddington units. The former value is consistent with Coroniti (1981) and the latter with Marscher and Jorstad (2011)....