My research has always focused on the applications of Einstein's theory of general relativity in astrophysics. During my professional career (beginning around 1968) astronomers have enormously increased the amount of the Universe that they can explore, and in so doing they have discovered an extraordinary range of unexpected phenomena, very many of which require general relativity for their explanation. These range from pulsars (neutron stars) and black holes on the small scale to gravitational lensing and the Big Bang on the large.
My research has followed this evolution by becoming more and more applied. I began by studying the stability and pulsation of rotating stars, mainly in order to understand neutron stars, which can spin many hundreds of times per second. Pulsating stars emit gravitational radiation, so I got interested in the problem of gravitational wave emission, especially by stars in binary systems, which are studied by post-Newtonian methods. This led to an interest in using numerical relativity to simulate the orbiting and merging of black holes in binary systems. The development of sensitive gravitational wave detectors led me to study gravitational wave data analysis in depth. This has occupied the majority of my research time in the past two decades.
I describe each of these interests in more detail below. In other sections I refer to my activities in software development (Triana) and publishing (Living Reviews and Open Access).