On May 22nd, the space telescope of Neil-Garrell Swift Observatory of NASA discovered a gamma ray burst in an extremely remote corner of space, which was called GRB 200522A. Scientists believe that this type of short explosion occurs when two neutron stars collide, so when the telescope sees one of them, it will frantically compete for observation data of other wavelengths in the electromagnetic spectrum. The collision happened about 5.5 billion years ago, but our telescope didn't receive these signals until now.
In the new study, the research team aimed some different space and ground telescopes at GRB 200522A, including NASA's Hubble Space Telescope, to observe the gap after the bright gamma ray burst. Using X-ray, radio and near infrared data, the team was able to measure the brightness of gamma ray bursts. But there is a special observation that does not meet the requirements. The near-infrared image from Hubble shows an extremely bright burst-about 10 times brighter than any 100 billion stars that have been seen before (although only a few have been observed so far).
"We were puzzled for some time and carefully studied all possible models," said Fang Wenhui, an astrophysicist at Northwest University and the first author of the new study. "The near infrared light we see from GRB 200522A is too bright to be explained by the standard radioactive energy nova."
The research team finally determined a model they called "a thousand new stars boosted by magnetic stars" to explain this extreme brightness. Two neutron stars collided in deep space, which may have produced magnetic stars. If confirmed, this will be the first time astronomers have discovered the birth of these extreme stars.
When two cosmic objects with high density, such as neutron stars and black holes, collide with each other, thousands of new stars will be produced. The merger process will eject a lot of subatomic materials into space, including gamma ray bursts. Fong said, you can think of it as a milkshake in a blender, but you forget to cover it, and the "neutron-rich" material flows into the universe.
The team's model shows that the creation of magnetars may stress thousands of nova events, making them much brighter than astronomers predicted. "If confirmed, it will be the first time that we can witness the birth of a magnetic star after the collision of two neutron stars," Fong said.
But researchers still have some work to do. Continuing to observe GRB 200522A with radio telescope will help to determine more clearly what happened before and after the gamma ray burst. The radio waves generated by this event should be able to confirm what is seen at infrared wavelength, but how long it takes for these waves to reach the earth depends on the environment around GRB 200522A. The model shows that it may take about six years for people to receive such signals, and Fong said that the team will monitor radio transmission in the next few years.
Magnetostars have long been mysterious cosmic stars, but last week, astronomers began to understand these elusive stars. Last week, a team of astrophysicists reported the discovery of a fast radio burst (FRB) of a magnetic star in the Milky Way. This important discovery shows that magnetars may sometimes produce these mysterious radio signals, but whether they can produce all FRB is still inconclusive. GRB 200522A may provide an opportunity to test this hypothesis again.
"If we can connect the FRB with the location of GRB 200522A, it will be an amazing discovery, which is really conclusive evidence to connect this special event with the magnetar," Fong said. However, she warned that it would be surprising if there was a connection between the short gamma ray burst itself and FRB. But gamma-ray bursts do constantly throw out new mysteries and cosmic problems that need to be solved. "I have been studying the same type of explosion for ten years, and the short-lived gamma ray burst can still surprise me." Fong pointed out.