Jim's Ph.D. Research Project
In this project, Jim tried to understand what causes the X-ray
variability in Cyg X-1. Because of these variations,
Cyg X-1 is a very interesting source, one which has been studied by
many but understood by few (if it is understood completely by anyone!).
Jim considered two possibilities: 1) the
variability was caused by a chaotic process but governed by a small set of
variable parameters (which could be easily modeled) and 2) the variability
could be explained by a traditional
shot noise model improved so that it more closely matched the observed
variability.
He found that the answer to 1) was that there was too much
noise in the data, which made it difficult to discern given the technique
he was using. The answer to 2) was "Yes! an improved shot-noise model
would work." Jim then developed an extension of the shot models. These
models were better at reproducing the observations, so they gave insight
into what physical processes in the Cyg X-1 system were occurring to cause
the observed variability.
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