Quasi-periodic oscillations in black-hole binaries
Abstract
Fast time variability is an important characteristic of black hole (BH) binaries and a key ingredient in understanding the physical processes in these systems. Fast time variability is generally studied through the inspection of power density spectra, whose component are either broad distributed over several decades in frequency or fairly narrow, in the form of localised peak (quasi-periodic oscillations, QPOs). It is now clear that QPOs are a common characteristic of accreting systems: they have been observed in accreting stellar mass BHs and neutron stars in X-ray binaries, in CVs, in ULXs and even in AGN. Even though their origin and nature is still debated, the study of QPOs provides a way to explore the inner accretion flow around accreting objects. Various models have been proposed to explain the origin of QPOs in black hole binaries, but only a few have been proved to be promising so far, having shown good agreement with observations. I will describe how timing is done in X-rays and how QPOs are usually studied. I will briefly review some of the proposed models and I will finally show the most recent results obtained on QPOs.
- Publication:
-
The Extremes of Black Hole Accretion
- Pub Date:
- July 2015
- Bibcode:
- 2015ebha.confE..10M