2008/03/31 by Ranjeev Misra, R. Misra, A. A. Zdziarski +1
Physics and Astronomy · #Accretion (finance) #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Astrophysics and Cosmic Phenomena #Degeneracy (biology) #Dissipation #Harmonic #Harmonic oscillator #RADIUS #Range (aeronautics) #Solar radius #Spectral line #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2008.13363.x
MNRAS (Letters), in press
arxiv created 2008/04/07 · openalex publication_date 2008/05/08 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We develop a model of an accretion disc in which the variability induced at a given radius is governed by a damped harmonic oscillator at the corresponding epicyclic frequency. That variability induces both linear and non-linear responses in the locally emitted radiation. The total observed variability of a source is the sum of these contributions over the disc radius weighted by the energy dissipation rate at each radius. It is shown that this simple model, which effectively has only three parameters including the normalization, can explain the range of the power spectra observed from Cyg X-1 in the soft state. Although a degeneracy between the black hole mass and the strength of the damping does not allow a unique determination of the mass, we can still constrain it to ≲(16–20) M⊙. We also show that our model preserves the observed linear rms–flux relationship even in the presence of the non-linear flux response.