Oregon Experimental Relativity Group: Characterizing and Mitigating Environmental Influences to Improve LIGO's Astrophysical Sensitivity

This award supports research in relativity and relativistic astrophysics, and it addresses the priority areas of NSF's "Windows on the Universe" Big Idea. The era of gravitational wave astronomy began with NSF's LIGO announcement of the detection of a black hole merger in 2016. This first detection led to a Nobel prize and spectacularly confirmed predictions of general relativity, but it also opened a new window into the universe.

We have since seen an amazing show through this new window: a cosmos continuously punctuated by collisions that, in energy, briefly outshine all of the stars in the universe. These dozens of black hole merger detections have allowed scientists to make ever-improving independent estimates of the age and expansion of the universe, and an ever-improving understanding of the population of black holes and the death of stars.

The detection of a neutron star merger in 2017 triggered radio and other telescopes to observe the aftermath, which, among other things, increased our understanding of the source of heavy elements like gold. In the future, continued observations, and increasing sensitivity will predictably promote the progress of science and our understanding of the universe, and, perhaps, reveal un- predicted phenomena.

The awardees will help make these discoveries by helping to increase the sensitivity of the LIGO detectors by studying and mitigating environmental influences (vibration, magnetic fields, radio waves, etc.) on the LIGO detectors. The team will train students in STEM areas.

In order to further increase sensitivity, LIGO must overcome known noise sources but also unknown and unexpected noise sources, many of which are driven by the environment. The proposed research will further the identification and mitigation of environmentally driven mystery noise sources that keep the detectors from reaching their design sensitivity.

The result will be that the detector becomes more sensitive and can see further into space, enabling new discoveries. The awardees will increase sensitivity for 200-300 solar mass black hole in-spirals, by developing characterization and mitigation techniques for scattered light noise, increase sensitivity to gravitational wave bursts and to stochastic backgrounds by developing methods to reduce the noise produced by lightning strokes thousands of kilometers away, increase sensitivity to continuous wave and transient sources by characterizing and mitigating electronics grounding fluctuation noise, and vet O4 gravitational wave candidates for environmental influences.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.