English: Artist’s impression of two neutron stars – the compact remnants of what were once massive stars – spiralling towards each other just before merging.

The collision of these dense, compact objects produced gravitational waves – fluctuations in the fabric of spacetime – that were detected by the LIGO/Virgo collaboration on 17 August 2017. A couple of seconds after that, ESA's Integral and NASA’s Fermi satellites detected a burst of gamma rays, the luminous counterpart to the gravitational waves emitted by the cosmic clash. This is the first discovery of gravitational waves and light coming from the same source.

Full story:Integral sees blast travelling with gravitational waves