Virgo status and commissioning results

Virgo is a French–Italian collaboration for the construction and operation of a 3 km long interferometric gravitational wave antenna. The construction of the detector is already completed and the commissioning is quite advanced, while the data taking is expected to start in 2005. In this paper, we report on the present status of Virgo and on the results of commissioning activity. In particular, we analyse the first four engineering runs (C1–C4) and discuss the sensitivity obtained in C4.