A source of irregular, repeated bursts of high-energy X-rays and low-energy gamma rays. Such events are believed to occur when the crust of a strongly magnetic neutron star (a magnetar) suddenly readjusts in a starquake, due to changes in the star's twisted magnetic field lines. The bursts usually last less than a second and can occur several times a day for a period of months. The source can then remain quiet for decades.
Subjects: Astronomy and Astrophysics.