Center of Gravity Seminar: Héctor Villarrubia Rojo

Title: Gravitational wave lensing: wave optics and GW231123

Abstract: Light travelling through the Universe is deflected by the intervening gravitational fields, a phenomenon known as gravitational lensing. This effect was an early prediction of General Relativity (GR) and it has become an essential tool in astronomy. The existence of gravitational waves was another prediction of GR, but in this case we had to wait until 2015 for the first detection. Since then, hundreds of events have been detected in LVK, a number that will increase significantly in the next observing run and with future detectors like LISA and the Einstein Telescope.

This large number of detections guarantees the eventual observation of lensed gravitational waves. Similarly to light, gravitational waves are affected by intervening matter, but with some important differences, e.g. they can experience diffraction. In this talk I will discuss the phenomenology of gravitational wave lensing, highlighting some key differences with light and focusing in the wave-optics regime. Finally, I will cover the exciting implications of the recently announced event GW231123, which can beconsidered to be the first serious candidate for a lensed GW.