Swift J1644+57: A White Dwarf Tidally Disrupted by a 10^4 M_{odot} Black Hole?
(3 votes over all institutions)
We propose that the remarkable object Swift J1644+57, in which multiple recurring hard X-ray flares were seen over a span of several days, is a system in which a white dwarf was tidally disrupted by an intermediate mass black hole. Disruption of a white dwarf rather than a main sequence star offers a number of advantages in understanding the multiple, and short, timescales seen in the light curve of this system. In particular, the short internal dynamical timescale of a white dwarf offers a more natural way of understanding the short rise times (~100s) observed. The relatively long intervals between flares (~5 x 10^4 s) may also be readily understood as the period between successive pericenter passages of the remnant white dwarf. In addition, the expected jet power is larger when a white dwarf is disrupted. If this model is correct, the black hole responsible must have mass < 10^5 M_{odot}.
