LIGO Seminar

We propose a class of binary black hole mergers within hierarchical triples, where a high-mass star in the outer orbit is accreting onto an inner binary composed of a pair of coalescing black holes. We show that the accretion flow could possibly drive the inner binary to merge much faster than it would purely due to gravitational radiation. We argue that this could greatly enhance the event rate of these binary mergers, making it a potentially important source of gravitational waves(GWs). Such accretion-driven binary black hole mergers are particularly interesting from an electromagnetic point of view. The binary black hole mergers are expected to be associated with matter outflows and possibly relativistic jets, with enhanced bolometric outbursts during the final merger. The inspiral phase of these binary black holes could be detectable by eLISA a few years before they enter the LIGO band. The presence of the third body could possibly be identified from gravitational waves alone due to the acceleration of the inner binary by the 3rd star.  In this talk, I will present the details of this model and discuss its implications to the multi-messenger observations of binary black hole merger.