Off-Line Subtraction of Seismic Newtonian Noise

Abstract

A fundamental limit for the sensitivity of an Interferometric Gravitational Wave detector in the low frequency region is imposed by the effect of environmental mass density fluctuations. These fluctuations generate stochastic gravitational fields which couple directly to the apparatus test masses, bypassing seismic isolation systems. In this paper the results of a preliminary investigation on the possibility of reducing this kind of noise are reported. We focus on the feasibility of off-line noise subtraction. In this approach the mass density fluctuations are monitored by an appropriate set of measurement devices. The resulting signals are combined linearly with the output of the interferometer to obtain partial cancellation of the noise.