LIGO's First Observing Run
Image credit: LIGO
This illustration shows the dates for two confirmed gravitational-wave detections by LIGO; and one candidate detection, which was too weak to unambiguously confirm. All three events occurred during the first four-month run of Advanced LIGO—the upgraded, more-sensitive version of the facilities. The three events are GW150914 (Sept. 14, 2015), LVT151012 (Oct. 12, 2015), and GW151226 (Dec. 26, 2015).