  Stationary (limiting) distributions of shot noise processes, with exponential
response functions, form a large subclass of positive selfdecomposable
distributions that we illustrate by many examples. These shot noise
distributions are described among selfdecomposable ones via the regular
variation at zero of their distribution functions. However, slow variation at
the origin of (an absolutely continuous) distribution function is incompatible
with selfdecomposability and this is shown in three examples.
