2012A&A...548A...3A

A dormant Swift source J164449.3+573451 (Sw 164449+57) recently experienced a powerful outburst, caused most probably by a tidal disruption of a star by the supermassive black hole at the center of the source. During the outburst, a quasi periodic oscillation (QPO) was detected in the observed X-ray flux from Sw 164449+57. We show that if the observed QPO belongs to a ``3:2 twin peak QPO'' (with the second frequency not observed), the mass of the black hole in Sw 164449+57 is rather low, M∼10⁵M_☉, and the source belongs to a class of intermediate mass black holes. The low mass of the source has been pointed out previously by several authors.