  We investigate the variability of Cygnus X-1 in the context of shot moise
models, and employ a peak detection algorithm to select individual shots. For a
long observation of the low, hard state, the distribution of time intervals
between shots is found to be consistent with a purely random process, contrary
to previous claims in the literature. The detected shots are fit to several
model templates and found to have a broad range of shapes. The fitted shots
have a distribution of timescales from below 10 milliseconds to above 1 second.
The coherence of the cross spectrum of light curves of these data in different
energy bands is also studied. The observed high coherence implies that the
transfer function between low and high energy variability is uniform. The
uniformity of the tranfer function implies that the observed distribution of
shot widths cannot have been acquired through Compton scattering. Our results
in combination with other results in the literature suggest that shot
luminosities are correlated with one another. We discuss how our experimental
methodology relates to non-linear models of variability.
