A massive explosion reveals a rare type of star never before seen outside the Milky Way

France – Astronomers detected a sudden explosion coming from a rare object in a galaxy close to the Milky Way, and this event led them to find the first magnetar to be discovered outside our galaxy.

Scientists believe the explosion must have been a rare giant flare erupting from a dead, highly magnetic star, a type of neutron star. It provides an opportunity to study an extremely rare event, and could help explain other types of unusual activity in the universe.

Such giant flares found by scientists are so unusual that we have only seen three of them in our galaxy and in the nearby Large Magellanic Cloud in the past fifty years. They can be difficult to see from a distance because it is difficult to tell where they come from.

In late 2023, the European Space Agency’s INTEGRAL satellite detected what appeared to be an explosion in part of the sky. For just a tenth of a second, the sky was illuminated by a brief flash of energetic gamma rays.

The data showed that the explosion came from the M82 galaxy, which is also called the Cigarette Galaxy, and is relatively close, as it is located about 12 million light-years from Earth.

“Gamma-ray bursts come from far away and anywhere in the sky, but this one came from a bright galaxy nearby,” said Sandro Mereghetti, of the National Institute of Astrophysics (INAF-IASF) in Italy, who led the work.

Scientists rushed to examine the explosion site, anticipating that they might see gravitational waves and the X-ray glow and light that are usually left when two neutron stars collide. But they could only see hot gas and stars. There were no X-rays or light signals, and no gravitational waves.

This led scientists to believe that the signal came from a magnetar, a type of neutron star with a particularly strong magnetic field, a type of remnant produced by the gravitational collapse of a massive star in a supernova. These celestial bodies emit flares that are sometimes huge, but very rare.

This is the first confirmation that such a magnetic flare comes from outside our Milky Way Galaxy.

Source: Independent