AIP Congress: New discoveries by LIGO during its first and second observing runs
December 13 @ 5:30 pm - 6:30 pm
The Advanced LIGO gravitational wave detectors have so far undertaken two observing runs, O1 and O2, with spectacular results. At the start of O1 in September 2015 the hundred year quest to directly detect gravitational waves on Earth was quickly realised with the detection of a clear and strong gravitational wave signal coming from the cataclysmic collision of two large black holes in a binary system some 1.3 billion years ago. Towards the end of O2 in August 2017 we achieved the long-anticipated discovery of two orbiting neutron stars in a binary system in the final moments of inspiral leading up to their violent collision. Within 1.7 seconds of the coalescence a gamma-ray burst was detected immediately confirming the long-held hypothesis that neutron star collisions are the progenitors of our almost daily detections of short gamma-ray bursts. Neutron stars are matter, so unlike when two black holes collide, they broadcast electromagnetic as well as gravitational radiation, and the alert sent out by LIGO caused an avalanche of telescopes and satellites around the world to interrupt their observing schedules to attempt to pinpoint and image the event. This was the birth of the era of multi messenger gravitational wave astronomy.
Since the end of O2, and while upgrading the instruments in preparation for O3, we have had the opportunity to analyse, in greater depth, the data from both O1 and O2 searching for coalescences of binary systems of black holes and neutron stars. In this talk we will announce the full catalogue of these results from both observing runs and explain the significance of these discoveries for physics.