The Advanced LIGO Detectors and the Detection of Gravitational Waves

On February 11, 2016 David Reitze, the LIGO Lab Executive Director, announced to the world the first direct detection of Gravitational Waves made by the LIGO Observatories. The detection of the inspiral and coalescence of two black holes is exciting not only as confirmation of Einstein's prediction of the existence of gravitational waves 100 years ago, but also as the first evidence for the existence of a coalescing binary black hole system and of black holes of several tens of solar masses. With the announcement of a second detection shortly afterwards we are witnessing the birth of a new branch of astronomy. In this talk the speaker will discuss what we have learned from the two detections. He will also talk about the formidable experimental challenges which had to be overcome to allow such detections to be made. The focus of the talk will be on several of the Advanced LIGO optical and laser subsystems.