Einstein’s gravitational waves and light produced by the same event – a pair of neutron stars – were detected for the first time in August 2017, an extraordinary moment in the history of physics.
The lecture will explain what gravitational waves are, and how they were discovered by the LIGO collaboration, initially for systems of binary black holes. We will then describe how optical flashes were detected in the case of the binary neutron star merger by the Dark Energy Survey (DES) and by other observatories around the world, across the electromagnetic spectrum. Instruments developed for other purposes turned out to be extremely useful for following up gravitational wave events. Such 'multi-messenger’ observations provide us with important information, from how gold is produced in stars to the nature of the expansion of the universe.
Ofer Lahav is Perren Chair of Astronomy at University College London. His research area is observational cosmology, in particular probing and characterising dark matter and dark energy. His work involves advanced statistical methods, eg, artificial intelligence for Big Data.
He is leading the UK consortium of the Dark Energy Survey, and he is co-director of UCL's Centre for Doctoral Training in Data-Intensive Science. He earned his PhD from the University of Cambridge, where he was a later a member of staff. He also served as Vice-President of the Royal Astronomical Society.
Image credit NSF/LIGO/Sonoma State University/A. Simonnet