Magnetic neutron star flare illuminates Cigar Galaxy

Astronomers have observed a rare and massive flare from a magnetar—an exceptionally magnetic neutron star—in the starburst galaxy Messier 82 (M82), located approximately 12 million light-years from Earth. The flare, which released as much energy in a tenth of a second as our sun emits in about 10,000 years, was detected by the European Space Agency's (ESA) Integral satellite on November 15, 2023. This event is the most distant magnetar flare ever recorded, with previous detections limited to our own Milky Way galaxy and its neighbor, the Large Magellanic Cloud.

Despite attempts by the XMM-Newton X-ray space telescope to find an afterglow from the explosion, none was found, leading an international research team, including experts from the University of Geneva, to confirm that the burst originated from a magnetar. The findings, published in the journal Nature, represent the first confirmed extragalactic magnetar flare detection.

Magnetars are distinguished by their intense magnetic fields, which are thousands of times stronger than those of ordinary neutron stars. This particular flare from M82 did not exhibit associated gravitational waves, which are typically expected from cataclysmic events like neutron star collisions. The rarity of such flares—only three confirmed instances in the past 50 years—highlights the significance of this discovery and suggests that many more magnetars, potentially emitting giant flares, could exist undetected in the universe.