|MadSci Network: Astronomy|
Without a reference, I selected my own. For a reference I used the following: http://www.youtube.com/watch?v=GAwO1okR074
Descriptions of what blackholes might do when merging is very much theoretical. The referenced simulation is of the physics; or, more specifically what general relativity says about the merging of blackholes unlimited by what is actually observable. From the simulation, one might deduce what aspects of the merger are observable, just as astronomical observations are studied to deduce what physics is actually represented.
To find the above reference, I used the search terms: +blackhole +merge
Thanks for your question.
Try the links in the MadSci Library for more information on Astronomy.