This special Physics department scheduled for Thursday 4/16/15 afternoon at 4 pm in Room 137. Coffee and cookies are served at 3:45 pm in the same room. Anyone is welcome.

When Galaxies Collide: the road to gravitational wave detection with pulsar timing arrays
Sydney J. Chamberlin, PhD Candidate, UWM Dept. of Physics

Gravitational waves are small perturbations to the spacetime structure of the universe. Predicted to exist by Einstein’s Theory of General Relativity, the direct detection of gravitational waves is currently a major goal in experimental astrophysics. At the low-frequency end of the detectable gravitational-wave spectrum, pulsar timing arrays exploit the stability of millisecond pulsars to search for gravitational waves. The gravitational waves in this frequency band are primarily generated by supermassive black hole binary systems, which occur (for instance) when galaxies collide. For a large number of such sources across the sky, gravitational waves can incoherently combine to form a stochastic background of gravitational waves.

In this talk, I will explain how pulsar timing arrays are used to search for gravitational waves, and describe some of the progress being made towards the first detections, with an emphasis on stochastic backgrounds. I will also explain how future stochastic background observations can be used to robustly test general relativity in a manner that is unique to pulsar timing arrays.