Noise from scattered light in Virgo's second science run data

Abstract\n16 IM-PAN 00-956 Warsaw a ; Warsaw University 00-681 Warsaw b ; Astronomical Observatory Warsaw University 00-478 Warsaw c ; CAMK-PAN 00-716 Warsaw d ; Biaa lystok University 15-424 Bial ystok e ; IPJ 05-400 wierk-Otwock f ; Institute of Astronomy 65-265 Zielona Gora g, Poland Noise from scattered light in Virgo's second science run data 3 Abstract. Virgo is one of the large, ground-based interferometers aimed at detecting gravitational waves. One of the technical problems limiting its sensitivity is caused by light in the output beams which is back-scattered by seismically excited surfaces and couples back into the main beam of the interferometer. The resulting noise was thoroughly studied, measured and mitigated before Virgo's second science run (VSR2). The residual noise during VSR2, which increases in periods with large microseism activity, is accurately predicted by the theoretical model. The scattered light has been associated with transient events in the gravitational-wave signal of the interferometer.