Period doubling and non-linear resonance in the black hole candidate IGR J17091-3624?

¹ Experimental Study Group, Massachusetts Institute of Technology, 77 Massachusetts Avenue, 02139 Cambridge ( MA), USA
e-mail: pao@space.mit.edu
² Copernicus Astronomical Center, ul. Bartycka 18, 00-716 Warszawa, Poland
e-mail: wlodek@camk.edu.pl; pam@camk.edu.pl
³ Department of Physics, University of Gothenburg, 412-96 Göteborg, Sweden
e-mail: marek.abramowicz@physics.gu.se
⁴ Institute of Physics, Faculty of Philosophy and Science, Silesian University in Opava, Bezručovo nám. 13, 746-01 Opava, Czech Republic

Received: 25 January 2012
Accepted: 10 March 2012

Abstract

The two high frequency quasi periodic oscillations (HFQPOs) recently reported in the black hole candidate IGR J17091-3624 are in a 5:2 frequency ratio (164 Hz to 66 Hz). This ratio is strongly suggestive of period doubling and nonlinear resonance analogous to phenomena known in RV Tauri-type pulsating stars (and recently discovered also in oscillations of RR Lyrae-type and of BL Herculis-type variables). An interpretation of the frequency ratio in terms of nonlinear interactions and a comparison with the HFQPOs reported in GRS 1915+105 may imply a mass of about six solar masses for the black hole in IGR J17091-3624.