Astronomers join hunt for Einsteins gravitational sirens

The first detection of gravitational waves was announced today by the LIGO/Virgo collaboration - and Leicester astronomers were among the first to respond to the detection, searching for the counterpart with X-ray and infra-red telescopes.

Gravitational waves were predicted by Einstein nearly a century ago. His theory of General Relativity says that the acceleration of massive bodies should produce gravitational waves, wobbles in the fabric of space and time which travel through the universe at the speed of light.  These waves are so small that only the violent acceleration of massive bodies gives signals we can hope to detect.

Last September, the latest generation of these detectors was undergoing tests when the first clear gravitational wave signal was picked up, as has been reported by the LIGO/Virgo collaboration today. This information was rapidly passed to astronomers, including a team from Leicester, allowing them to join a world-wide hunt to identify the source of the mysterious waves. 

The Leicester team first used the Swift satellite to scan the region looking for X-rays from the explosion caused by the collision. They reported the detection of 3 X-ray sources just 15 hours after the receiving news of the gravitational wave event, although it turned out that these objects were not related to the Gravitational Waves. A few days later they used the world’s most powerful infrared telescope, the VISTA telescope situated in Chile, to hunt for the collision remnant since infrared light is also expected to be produced in such events. After weeks of analysis no counterpart was found in these images. This result is consistent with the latest analysis of the gravitational wave data, which confirmed that the source was actually likely to be a merger of two black holes, and therefore not expected to emit light in any form, either X-ray or in infrared.

Professor Nial Tanvir from the Department of Physics and Astronomy said: “Although on this occasion our hunt for light was unsuccessful, nonetheless, the first detection of gravitational waves heralds a new era of physics and astronomy, in which we will be able to study these most violent of cosmic collisions using both gravitational and electromagnetic radiation."