Status of ANTARES, an undersea neutrino telescope

The ANTARES collaboration is building a large undersea telescope located at 2500 m depth in front of the Toulon shore with the main purpose to search for high-energy neutrinos from astrophysical sources. Neutrinos are detected through the Cherenkov light emitted by the muons produced in the neutrino interaction with the matter surrounding the detector. A 40 km long electro-optical cable connects the site to the shore. A prototype line consisting of a string of 15 PMTs and an instrumented line to monitor the environmental parameters have been successfully deployed and connected to the main cable using a manned submarine. The description and the expected performances of the full telescope as well as some preliminary results from the prototyping phase are presented.