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Session: Cosmology and Relativistic Astrophysics

Name: Prof. Apostolos Mastichiadis (National & Kapodistrian Univ. of Athens)
Coauthors: No coauthors were included.
Type: Oral
Title: A study of natural frequencies in a dynamic corona – disk system
Abstract:

Black-hole X-ray binaries (BHXRBs) in the hard and hard-intermediate spectral and temporal states exhibit in their power spectra characteristic frequencies called type-C quasi-periodic oscillations (QPOs). Noting that the hot Comptonizing corona interacting with the cold accretion disk, both of which are central in understanding BHXRBs, is essentially a dynamical system, we write and solve the time-dependent equations that describe energy conservation. For a constant mass accretion rate, the dynamic corona – disk system exhibits dumped oscillations with characteristic frequencies similar to the ones observed in the power spectra of BHXRBs. Even small perturbations in the accretion rate are able to sustain the oscillations. We argue, therefore, that type-C QPOs in BHXRBs could, in principle, arise from the interaction of the hot Comptonizing corona with the much colder accretion disk.