Correlation of geophysical factors with results of gravity wave detection experiments

The possible influence of variations in the daily-average sunspot number (W) and geomagnetic-wave amplitude (Ap) on the detections of gravitational-radiation events (GREs) reported by Brown et al. (1982) for a 440-d period in 1979-1981 is investigated statistically. An era-superposition technique is applied to compare 18 GRE periods and 20 non-GRE periods of 7 d each. Both Ap and W are found to be correlated with the GRE signals (the Ap peaking on the day of the GRE), and a bias toward daylight hours for GRE detection (62 percent of GREs in daylight and 43 percent of those between 10 AM and 2 PM local time) is noted. It is inferred that shielded gravitational-wave antennas may be subject to atmospheric EM noise too weak to be detected with available magnetometers. 10 references