A technique to modulate the signature of a stochastic gravitational wave background

Detecting a stationary, stochastic gravitational wave signal is complicated by the impossibility of observing detector noise independently of the signal. Here we describe a method of identifying this source of systematic error by varying the orientation of one of the detectors, leading to separate and independent modulations of the signal and noise contribution to the cross-correlation. The method can be applied to measurements of a stochastic gravitational wave background by the ALLEGRO/LIGO Livingston Observatory detector pair. We explore—in the context of this detector pair—how this new measurement technique is insensitive to a cross-correlated detector noise component that can confound a conventional measurement. PACS numbers: 0480N, 0480, 9555Y (Some figures in this article are in colour only in the electronic version)