Flux modulation from the Rossby wave instability in microquasars’ accretion disks: toward a HFQPO model

¹ AstroParticule et Cosmologie (APC), Université Paris Diderot, 10 rue A. Domon et L. Duquet, 75205 Paris Cedex 13, France
e-mail: frederic.vincent@obspm.fr
² Physikalisches Institut, Universität Bern, 3012 Bern, Switzerland
³ CEA, Irfu, SAp, Centre de Saclay, 91191 Gif-sur-Yvette, France
e-mail: heloise.meheut@cea.fr
⁴ LESIA, Observatoire de Paris, CNRS, Université Pierre et Marie Curie, Université Paris Diderot, 5 place Jules Janssen, 92190 Meudon, France

Received: 5 November 2012
Accepted: 4 January 2013

Abstract

Context. There has been a long string of efforts to understand the source of the variability observed in microquasars, especially concerning the elusive high-frequency quasi-periodic oscillation. These oscillations are among the fastest phenomena that affect matter in the vicinity of stellar black holes and therefore could be used as probes of strong-field general relativity. Nevertheless, no model has yet gained wide acceptance.

Aims. The aim of this article is to investigate the model derived from the occurrence of the Rossby wave instability at the inner edge of the accretion disk. In particular, our goal here is to demonstrate the capacity of this instability to modulate the observed flux in agreement with the observed results.

Methods. We used the AMRVAC hydrodynamical code to model the instability in a 3D optically thin disk. The GYOTO ray-tracing code was then used to compute the associated light curve.

Results. We show that the 3D Rossby wave instability is able to modulate the flux well within the observed limits. We highlight that 2D simulations allow us to obtain the same general characteristics of the light curve as 3D calculations. With the time resolution we adopted in this work, 3D simulations do not give rise to any new observable features that could be detected by current instrumentation or archive data.