Mass estimate of the Swift J 164449.3+573451 supermassive black hole based on the 3:2 QPO resonance hypothesis

¹ Copernicus Astronomical Center, ul. Bartycka 18, 00-716 Warszawa, Poland
² Physics Department, Gothenburg University, 412-96 Göteborg, Sweden
e-mail: smarek.abramowicz@physics.gu.se
³ Astronomy Department, Peking University, 100871 Beijing, PR China
e-mail: fkliu@pku.edu.cn

Received: 18 August 2012
Accepted: 30 September 2012

Abstract

A dormant Swift source J 164449.3+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 ~ 10⁵ M_⊙, 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.