The technology required for gravitational wave detection is astounding in its ingenuity and precision and the data processing is at the forefront of signal processing techniques and capacity. However, we need dedicated, coordinated efforts by astronomers to monitor the time domain Universe using recent technological advances and innovative techniques, to identify the counterparts to gravitational wave sources, pinpoint their locations and measure their distances. Under the direction of Professor Matthew Bailes, OzGrav's Astrophysics Theme advances three major research programs;
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major programs
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The main aim of the Observations project is to detect the electromagnetic radiation associated with gravitational waves (GW). The initial detection would be a landmark moment for astrophysics, initiating a new era of multi-messenger astronomy and providing a powerful means to explore and understand our Universe. GW counterpart identifications and distance measurements are essential to fully understand their nature. Maximising the potential offered by GW observations involves the development of a worldwide, multi-wavelength, multi-messenger network for electromagnetic follow up. Australia dominates the radio and optical coverage and detection capabilities of the Southern sky. OzGrav will provide a long-term, strong, coordinated global network of detection facilities that utilise recent technological advances and observational techniques to detect and fully characterise GW events, firmly placing Australia at the leading edge in this exciting new field.
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Sources Program Leader: Prof Yuri Levin
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In terms of the source of gravitational wave radiation, what OzGrav scientists will model depends to some extent on what will be detected. Globular clusters (GCs) contain hundreds of thousands (some up to several millions) of single, exotic and binary stars packed into a dense environment. They are a potentially rich source of gravitational wave mergers , but direct N–body simulations are required to quantify the expected numbers and properties. Other potential sources include Low-mass X-ray Binaries (LMXBs), and binary black holes at the centres of galaxies.
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Gravity Program Leader: Prof Susan Scott
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Gravitational waves are produced most efficiently by relativistic astrophysical objects that strongly warp spacetime in their vicinity. This warping contributes up to 30 percent of a neutron-star rest mass, and the entirety of a black hole mass. Thus the minute gravitational waves we measure on Earth are produced by localised, strongly nonlinear dynamics of the warped spacetime elsewhere in the Universe. Measuring gravitational waves will probe gravity in a regime that is not accessible to any other method of observation, and will provide insight into the mysterious world of extremely relativistic objects. The relativity theorists have done their homework. After 40 years of hard work, they can reliably perform high-precision numerical experiments with mergers of black holes and neutron stars, and can compute expected gravitational waveforms through a variety of sophisticated numerical and analytical techniques. This, combined with the GW signal detected by advanced LIGO, will for the first time present an opportunity to test Einstein’s GR in strongly relativistic regime.
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Key Astrophysical Questions:
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