A Fourier Transformed Bremsstrahlung Flash Model for the Production of X-Ray Time Lags in Accreting Black Hole Sources
arXiv:1406.0871 · doi:10.1088/2041-8205/785/2/L34
Abstract
Accreting black hole sources show a wide variety of rapid time variability, including the manifestation of time lags during X-ray transients, in which a delay (phase shift) is observed between the Fourier components of the hard and soft spectra. Despite a large body of observational evidence for time lags, no fundamental physical explanation for the origin of this phenomenon has been presented. We develop a new theoretical model for the production of X-ray time lags based on an exact analytical solution for the Fourier transform describing the diffusion and Comptonization of seed photons propagating through a spherical corona. The resulting Green's function can be convolved with any source distribution to compute the associated Fourier transform and time lags, hence allowing us to explore a wide variety of injection scenarios. We show that thermal Comptonization is able to self-consistently explain both the X-ray time lags and the steady-state (quiescent) X-ray spectrum observed in the low-hard state of Cyg X-1. The reprocessing of bremsstrahlung seed photons produces X-ray time lags that diminish with increasing Fourier frequency, in agreement with the observations for a wide range of sources.
References in corpus (7)
- RXTE Observation of Cygnus X-1: II. Timing Analysis
- The broad-band spectrum of Cygnus X-1 measured by INTEGRAL
- RXTE Observation of Cygnus X--1: III. Implications for Compton Corona and ADAF Models
- A general relativistic model of accretion disks with coronae surrounding Kerr black holes
- Probing the Structure of Accreting Compact Sources Through X-Ray Time Lags and Spectra
- Exact solution for the Green's function describing time-dependent thermal Comptonization
- Time Lags in Compact Objects: Constraints on the Emission Models
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- Fourier Analysis of Blazar Variability
- Time-Dependent Electron Acceleration in Blazar Transients: X-Ray Time Lags and Spectral Formation
- Fourier Analysis of Blazar Variability: Klein-Nishina Effects and the Jet Scattering Environment
- An Integrated Model for the Production of X-Ray Time Lags and Quiescent Spectra from Homogeneous and Inhomogeneous Black Hole Accretion Coronae