Astronomers have found a pair of extraordinary cosmic objects that dramatically burst in X-rays, flaring up to become about a hundred times brighter in less than a minute, before returning to original X-ray levels after about an hour. This discovery may represent a new class of explosive events found in space.
On 14 September 2015, gravitational waves produced by a pair of merging black holes gently rattled space-time in the vicinity of Earth. Less than half a second later, NASA’s Fermi Gamma-ray Space Telescope picked up a brief, weak burst of high-energy light consistent with the same part of the sky. Analysis of this burst suggests that the events are connected.