Removal of interference from external coherent signals

Abstract

We present a technique that we call coherent line removal, for removing external coherent interference from gravitational wave interferometer data. We illustrate the usefulness of this technique applying it to the the data produced by the Glasgow laser interferometer in 1996 and removing all those lines corresponding to the electricity supply frequency and its harmonics. We also find that this method seems to reduce the level of non-Gaussian noise present in the interferometer and therefore, it can raise the sensitivity and duty cycle of the detectors.