  This paper reviews gravitational wave sources and their detection. One of the
most exciting potential sources of gravitational waves are coalescing binary
black hole systems. They can occur on all mass scales and be formed in numerous
ways, many of which are not understood. They are generally invisible in
electromagnetic waves, and they provide opportunities for deep investigation of
Einstein's general theory of relativity. Sect. 1 of this paper considers ways
that binary black holes can be created in the universe, and includes the
prediction that binary black hole coalescence events are likely to be the first
gravitational wave sources to be detected. The next parts of this paper address
the detection of chirp waveforms from coalescence events in noisy data. Such
analysis is computationally intensive. Sect. 2 reviews a new and powerful
method of signal detection based on the GPU-implemented summed parallel
infinite impulse response filters. Such filters are intrinsically real time
alorithms, that can be used to rapidly detect and localise signals. Sect. 3 of
the paper reviews the use of GPU processors for rapid searching for
gravitational wave bursts that can arise from black hole births and
coalescences. In sect. 4 the use of GPU processors to enable fast efficient
statistical significance testing of gravitational wave event candidates is
reviewed. Sect. 5 of this paper addresses the method of multimessenger
astronomy where the discovery of electromagnetic counterparts of gravitational
wave events can be used to identify sources, understand their nature and obtain
much greater science outcomes from each identified event.
