Will the level of seismic noise at Livingston Observatory interfere with the detection of gravity waves from binary inspirals?

Abstract

A major impediment to gravity wave detection in interferometer detectors such as Laser Interferometer Gravitational Wave Observatory (LIGO) is nongravitational wave-induced motion of the test masses. All types of noise sources including environmental sources contribute to this problem. Seismic motion is a significant source of such motion. I introduce a method to quantify the contribution of a given noise source to motion that is most deleterious to gravity wave detection, e.g., motion that mimics gravity wave signatures. I define such a benchmark in two senses: A relative benchmark that quantifies the degree of intrinsic interference with the gravity wave detection and an absolute benchmark which incorporates scaling factors appropriate to a given experiment. To give statistical meaning to the method and to illustrate it, I benchmark Gaussian noise and seismic colored Gaussian noise; both benchmark at 0 false events/day, which, applying a simple statistical model, implies ≪1 event for even year-long data runs. Finally, the relative benchmark for seismic noise at the Livingston observatory is (for the band from ∼100–400 Hz), using two 24 h data sets, 40–290 false events/day. Given the LIGO I noise curves, it is shown that the seismic noise should not interfere with the detection of binary inspiral generated gravity waves using optimal filtering. Its absolute benchmark is 0 false events/day, which, applying as above a simple statistical model, implies ≪1 event/year. In rough terms, if only Livingston seismic noise and gravity waves were impinging on the detector, one would expect to see neutron star binary inspiral’s that occur anywhere in the universe.