Séminaires, soutenances

Gravitational waves don't go on holiday! The week of the 15th of August seen from the perspective of the Virgo experiment

by Nicolas ARNAUD (LAL)

Amphi Recherche (Dpt de Physique)

Amphi Recherche

Dpt de Physique


Following a multi-year upgrade program and an intense phase of commissioning, the Advanced Virgo detector joined the two twin Advanced LIGO detectors on August 1st, 2017. During the four weeks of common data taking for the global three-detector network, promising gravitational-wave candidates were identified. Among which two discoveries which have been published this Fall: GW170814, another stellar mass binary black hole coalescence and the first signal ever seen by three gravitational-wave detectors; three days later GW170817, the first binary neutron star coalescence detected. Thanks to the accuracy of the 3D-localization of the GW170817 source by the LIGO-Virgo network, the optical counterpart of the merger was identified only about 11 hours after the gravitational-wave signal had been recorded. And its evolution could then be observed for weeks, over multiple wavelengths by tens of telescopes worldwide.

After an introduction to gravitational waves and their search by ground-based giant interferometric detectors, I will describe the Advanced Virgo commissioning and subsequent data taking period, before focusing on GW170814 and GW170817. The latter in particular is one of the golden events envisioned three decades ago when the LIGO and Virgo projects started being designed: it marks the beginning of the multi-messenger astronomy with gravitational waves. I will conclude my talk by showing some prospects for the LIGO-Virgo network, whose detectors should improve their sensitivity during the current one-year shutdown period.