Disk warping and black hole X-ray binaries

Astronomy and Astrophysics, vol. 710, pp. A387

Abstract

Context. X-ray binaries exhibit complex variability patterns studied in the power spectrum. These include the broadband noise (BBN) components and various types of narrow components called quasi-periodic oscillations (QPOs). There is currently no consensus about what determines the presence or absence of the BBN or what generates the QPOs. Many believe that QPO generation is due to frame-dragging effects caused by Lense–Thirring torques. Aims. We investigated the potential impact of frame-dragging effects on the accretion disk itself. In particular, we focused on its impact on the observed variability and on the presence (and types) of associated QPOs. Methods. We made analytical estimates to assess the potential presence of a geometric warp in the inner accretion disk during state transitions. Results. We show that the presence of a warp can modify the spectral-timing properties in a way that matches the observed transition between QPO types during outbursts. We also discuss the peculiar case of Cyg X-1, as well as how the hard-to-soft transition could be driven by the warp itself. Conclusions. The (expected) emergence of a warp provides a consistent explanation for the evolution of both the BBN and the QPO properties during state transitions. This offers a first path toward unifying the variability of black hole X-ray binaries.

Authors 8

1. G. Marcel
   Affiliation as printed

   Department of Physics and Astronomy

2. Benjamin Ricketts Aachen

   Space Research Organisation Netherlands · University of Amsterdam

   Affiliation as printed

   Anton Pannekoek Institute, University of Amsterdam

   SRON

3. Vanessa López-Barquero

   University of Maryland, College Park

   Affiliation as printed

   Department of Astronomy, University of Maryland

4. D. J. K. Buisson

   Institute for Space Astrophysics and Planetology · University of Southampton · National Institute for Astrophysics

   Affiliation as printed

   Fluid and Complex Systems Centre

   INAF–Istituto di Astrofisica e Planetologia Spaziali

   School of Physics & Astronomy, University of Southampton

5. Federico M. Vincentelli

   University of Southampton

   Affiliation as printed

   School of Physics & Astronomy, University of Southampton

6. Matthew J. Middleton

   University of Maryland, College Park

   Affiliation as printed

   Department of Astronomy, University of Maryland

7. Christopher S. Reynolds

   Institute of Science and Technology Austria

   Affiliation as printed

   Institute of Science and Technology Austria

8. Mark Avara
   Affiliation as printed

   Department of Physics and Astronomy