LIGO

In October 2018, the IGFAE joined the LIGO Scientific Collaboration (LSC), an initiative focused on gravitational wave (GW) science. Gravitational waves are wrinkles or oscillations in space-time, which were anticipated by Einstein more than 100 years ago. They were first observed experimentally in September 2015, by the Laser interferometer Gravitational-Wave Observatory (LIGO).

These first detections of gravitational waves were recognised, among others, with the 2016 Special Prize for Breakthrough in Fundamental Physics for the LSC and Virgo collaborations – including two IGFAE members – and the 2017 Nobel Prize in Physics for three pioneering LIGO scientists.

Following the detection of 90 gravitational wave signals in the first three observing periods of the advanced LIGO and Virgo detectors until 2020, the data exchange network was extended with the new cryogenic KAGRA detector in Japan. The fourth observing round started in May 2023 with increased network sensitivity, and has already reached 200 detections in less than two years.

After being accredited as a María de Maeztu Unit of Excellence in 2017, the scientific management of the IGFAE identified gravitational wave science as a line of research with a particularly high potential impact, especially in relation to multimessenger astrophysics. This is a branch of astrophysics that aims to exploit the detection of different types of signals (photons, GW, cosmic rays, neutrinos) to improve and complement information from astrophysical sources. The new research line opened at IGFAE also has synergies with the current activities of the Institute, in particular with the strong theoretical involvement in many aspects of gravity, the use of gravitational waves as probes of ultra-dense nuclear matter in neutron stars, as well as with the experimental activities in the framework of the Pierre Auger Observatory, the largest and most accurate ultra-high energy cosmic ray detector in the world.