Abstract:

The age of gravitational wave astronomy has dawned: we now have a new form of radiation with which to study the Universe. On September 14, 2015, the Laser Interferometer Gravitational Wave Observatory (LIGO) detectors recorded the first direct observation by humankind of gravitational waves -- space-time distortions generated by objects with extreme gravity. These waves propagate over astrophysical distances and can be detected by the modulation imposed on the optical path of a suspended mirror laser interferometer. Modern laser interferometric gravitational wave detectors are giant, broadband opto-mechanical sensors that explore the audio spectrum from 1 Hz to 10 kHz. This entire frequency band is expected to contain signals from dynamical astrophysical processes of great interest, such as the inspiral and merger of compact objects, stellar core-collapse supernovae, spinning neutron stars and various astrophysical backgrounds. Even more tantalising are the unpredicted sources. I will discuss gravitational waves and the technology and instrumentation developed to detect them. I will describe what we have observed so far, and the instrumentation-focussed research program at the Australian National University aiming to expand the horizons of gravitational wave detectors by attacking the limiting noise sources, of fundamental and technical origin.