Physics Colloquium with Jonathan Katz on Outliers and Log-Normal Widths: Characterizing Distributions

I will address two problems often encountered in astronomical data:

1. Often one member of a dataset appears to be an outlier---is some property (brightness, etc.) so extreme that it cannot be described by the same distribution that characterizes other members.  The first example of this may be Nova 1885 in what we now know as the Andromeda Galaxy, whose luminosity was orders of magnitude greater than those of other novae.  We now know that Nova 1885 was a supernova, distinct from ordinary Galactic novae.
2. If a distribution of some parameter (for example, intervals between bursts of some repeating Fast Radio Bursts) is well-fit by a log-normal function, then the width of this fuction is a dimensionless number that characterizes the dynamics, in analogy to critical exponents in  statistical mechanics. Comparing values of this dimensionless number may reveal common dynamics in apparently unrelated processes.