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[17.12] A Diffusion Model Applied to Soft X-ray Transients and Other X-ray Sources

K. S. Wood, P. S. Ray, M. T. Wolff, M. N. Lovellette (NRL), L. Titarchuk (GMU), R. Bandyopadhyay (Oxford), E. Bloom, P. Saz Parkinson, D. Tournear, W. Focke, K. Reilly, B. Giebels (SLAC), J. Scargle (NASA-Ames)

This presentation summarizes the linear diffusion model applied to the evolution of the double-peaked outburst in the transient source XTE J1118+480. The model treats the two outbursts as episodic mass deposition at the outer radius of the disk followed by evolution of disk structure according to a diffusion process. Light curves with fast-rise, exponential decay profile are a general consequence of the diffusion process. Deconvolution of the light curve proves to be feasible and gives an input function specifying mass deposition at the outer disk edge as well as the total mass of the disk, both as functions of time. The derived evolution of total disk mass can be correlated with the observed evolution of the ~ 0.1 Hz QPO as observed by USA and RXTE. We discuss how the model applies to other transients and other X-ray outbursts.

Basic research in X-ray astronomy at the Naval Research Laboratory is supported by ONR/NRL. Work at SLAC was supported by Department of Energy contract DE-AC 03-76-SFO0515.

Bulletin of the American Astronomical Society, 35#2
© 2003. The American Astronomical Soceity.