Spectral signature of oscillating slender tori surrounding Kerr black holes

¹ Nicolaus Copernicus Astronomical Center, ul. Bartycka 18, 00-716 Warszawa, Poland
e-mail: fvincent@camk.edu.pl
² Faculty of Physics, Warsaw University, ul. Hoza 69, 00-681 Warszawa, Poland
e-mail: gmazur@camk.edu.pl
³ LUTH, Observatoire de Paris, CNRS, Université Paris Diderot, 5 place Jules Janssen, 92190 Meudon, France
e-mail: odele.straub@obspm.fr
⁴ Physics Department, Gothenburg University, 412-96 Göteborg, Sweden
e-mail: marek.abramowicz@physics.gu.se
⁵ Institute of Physics, Faculty of Philosophy and Science, Silesian University in Opava, Bezrucovo nam. 13, 746 01 Opava, Czech Republic
e-mail: gabriel.torok@gmail.com; pavel.bakala@fpf.slu.cz

Received: 21 November 2013
Accepted: 22 January 2014

Abstract

Context. Some microquasars exhibit millisecond quasi-periodic oscillations (QPO) that are most probably related to phenomena occuring in the immediate vicinity of central black holes. Oscillations of accretion tori have been proposed to model these QPOs.

Aims. Here, we aim at determining the observable spectral signature of slender accretion tori surrounding Kerr black holes. We analyse the impact of the inclination and spin parameters on the power spectra.

Methods. Ray-traced power spectra of slender tori oscillation modes are computed in the Kerr metric.

Results. We show that the power spectral densities of oscillating tori are very sensitive to the inclination and spin parameters. This strong dependency of the temporal spectra on inclination and spin may lead to observable constraints of these parameters.

Conclusions. This work goes a step further in the analysis of the oscillating torus QPO model. It is part of a long-term study that will ultimately lead to comparison with observed data.