  In previous work, we established theoretical results concerning the effect of
matter shells surrounding a gravitational wave (GW) source, and we now apply
these results to astrophysical scenarios. Firstly, it is shown that GW echoes
that are claimed to be present in LIGO data of certain events, could not have
been caused by a matter shell. However, it is also shown that there are
scenarios in which matter shells could make modifications of order a few
percent to a GW signal; these scenarios include binary black hole mergers,
binary neutron star mergers, and core collapse supernovae.

General Relativity and Quantum Cosmology