During the final moments of a binary black hole (BH) merger, the
gravitational wave (GW) luminosity of the system is greater than the combined
electromagnetic output of the entire observable universe. However, the
extremely weak coupling between GWs and ordinary matter makes these waves very
difficult to detect directly. Fortunately, the inspiraling BH system will
interact strongly--on a purely Newtonian level--with any surrounding material
in the host galaxy, and this matter can in turn produce unique electromagnetic
(EM) signals detectable at Earth. By identifying EM counterparts to GW sources,
we will be able to study the host environments of the merging BHs, in turn
greatly expanding the scientific yield of a mission like LISA.Comment: 10 pages, 1 figure, submitted to Class. Quantum Grav. special issue:
proceedings of 8th LISA Symposiu