# Coalescing Compact Binaries

## Searching for Compact Binary Coalescence

One of the most promising sources of gravitational waves is expected to be the radiation produced by binary systems consisting of compact objects, such as neutron stars and black holes. Hulse and Taylor were awarded the 1993 Nobel Prize in Physics for the discovery of such a binary system, where the observation of a pulsar in the binary provided indirect evidence of the existence of gravitational waves.

As the orbit of such systems continues to decay, the stars move closer and faster, producing more intense GWs, and finally coalescing in a burst of gravitational radiation. This final in-spiral and merger stage is one of the primary targets for current and next generation gravitational wave detectors, and its observation will afford us a unique opportunity to test Einstein's theory of General Relativity in the strong field regime.

At Birmingham, we are working on the development of data analysis algorithms which can examine such signals and infer the properties of the originating system, such as the masses, positions and spins of the black holes/neutron stars. Using techniques such as Markov Chain Monte Carlo sampling and nested sampling of probability distributions, enabled by our computing resources including the Birmingham Tsunami and Blue BEAR Beowulf clusters, we can extract the maximum possible astronphysical information from the observational data.

In additional to ground-based observations, the LISA mission will detect thousands of such signals from the population of white-dwarf binaries in the Milky Way; and from supermassive black holes at cosmological distances, which will provide a new probe of the history of structure formation in the Universe.

Recent publications:- J. Veitch and A. Vecchio, Classical and Quantum Gravity, 25 (2008) 184010i
- J. Veitch and A. Vecchio, Physical Review D, 78 (2008) 022001