Gravitational waves are oscillations in the curvature of space-time produced by the most violent phenomena of the cosmos: the explosion of a star, the collision between stars with ultra-dense neutrons or the fusion of black holes. Researchers around the world have been tracking Gravitational Waves (GW) for decades.

KEY DATES for Elgar and Gravitational Waves

1915

• Albert Einstein predicts the existence of GW in his theory of General Relativity.

1991

• Atom interference (AI) techniques were used in proof-of-principle work to measure rotations and accelerations

1994

• Start of the construction of large GW detectors with the LIGO (USA) and the VIRGO (FR-IT) Programs.

1997-2016

• Atom interferometer instruments reach and even superseed classical devices for inertial measurements.

2002-2007

• Commissioning and first operations of LIGO and VIRGO

2012

• Funding of MIGA in France, the first large scale measurement based on AI to provide highly sensitive gravity measurement resolved in time and space.

2015

• First Gravitational Wave detection from the emission of a black hole binary systems by LIGO detector.

2017

• French national research agency (ANR) labels a project to study
the construction of a European infrastructure based on large scale
AI: The European Laboratory for Gravitational and Atom-interferometric Research (ELGAR)

2019

• Physicists from across Europe release the ELGAR paper (arXiv:1911.03701r): a plan for setting up a huge underground GW observatory that, if funded, could be operational by the mid-2030s

European funding application of ELGAR to carry out a detailed design and costing for the facility.

2020

• if funded ELGAR Design Study starts (April)

• First simultaneous observation
by LIGO and VIRGO of GWs from a Neutron Star binary system with an electromagnetic counterpart.
+ Using several instruments spread over the globe is an asset to consolidate and refine the observations.

2018

• First catalog of GW sources representing eleven events.