The VIRGO interferometer for gravitational wave detection.

The Virgo gravitational wave detector is an interferometer with 3 km long arms in construction near Pisa in Italy. The accessible sources at the design sensitivity and main noises are reviewed. Virgo has devoted a significant effort to extend sensitivity to low frequency reaching the strain level h = 10 −21 Hz −1/2 at 10 Hz while at 200 Hz h = 3 · 10 −23 Hz −1/2 . Design choices and status of construction are presented.