Why look for black hole coalesences?

• According to Flanagan and Hughes (PRD57 (1998)), the coalescence of two black holes may release up to 10 times as much energy as the inspiral before it.
• This means that coalescence will be visible to much greater distances, approximately 10 times further away.
• They conclude that, even if these systems are 10000 times less numerous than neutron star binaries, they will likely be the first source seen.
• No reliable theoretical model means there is much to be learned from observations, but ...
• No reliable theoretical model means we don't know what we are looking for.