WASHINGTON — Magnetars are among the universe's most extreme objects: a class of the compact stellar remnants called neutron stars that possess immensely strong magnetic fields. Once in a while, they produce enormous eruptions of gamma rays in the strongest nondestructive release of energy known in the cosmos.Scientists have now detected the most distant-known instance of one of these eruptions, called a giant flare, from a magnetar residing in a galaxy called Messier 82, or M82.
While there are more energetic cosmic events such as supernova explosions at the end of a massive star's life and gamma-ray bursts caused by two neutron stars merging, those involve destruction, unlike giant flares. Magnetars also emit occasional surges of gamma rays and X-rays at lower energy levels than giant flares.Neutron stars are born in the explosion and collapse of stars eight to 25 times the mass of the sun at the end of their life cycle.