Subtraction of correlated noise in global networks of gravitational-wave   interferometers
  The recent discovery of merging black holes suggests that a stochastic gravitational-wave background is within reach of the advanced detector network operating at design sensitivity. However, correlated magnetic noise from Schumann resonances threatens to contaminate observation of a stochastic background. In this paper, we report on the first effort to eliminate intercontinental correlated noise from Schumann resonances using Wiener filtering. Using magnetometers as proxies for gravitational-wave detectors, we demonstrate as much as a factor of two reduction in the coherence between magnetometers on different continents. While much work remains to be done, our results constitute a proof-of-principle and motivate follow-up studies with a dedicated array of magnetometers. 
Michael W. Coughlin, Nelson L. Christensen, Rosario De Rosa, Irene   Fiori, Mark Go{\l}kowski, Melissa Guidry, Jan Harms, Je...
gr-qc astro-ph.IM physics.ins-det