A weird gamma ray burst doesn’t fit our understanding of the cosmos

Astronomers have noticed an odd blast of gamma radiation from house that defies categorisation, and it could imply a spot in our understanding of how black holes kind

By Leah Crane

A wierd blast of radiation from house might upend how we categorise such flashes, referred to as gamma ray bursts (GRBs). It appears to come back from a black gap forming surprisingly slowly after two stars merge, indicating a spot in our understanding of black holes.

There are two primary forms of gamma ray bursts: quick GRBs, which final lower than 2 seconds and customarily happen when two neutron stars smash collectively and collapse right into a black gap, and lengthy GRBs, which may final minutes and are related to supernovas. But GRB 211211A, noticed in 2021, doesn’t slot in that dichotomy.

Four separate analysis teams noticed the GRB, they usually all noticed the identical factor: it undoubtedly got here from two stars colliding, but it surely lasted about one minute. “Two seconds is how long it takes in a merger for a black hole to form and eat up everything in its environment, so it’s very strange that this lasted a whole minute,” says Benjamin Gompertz on the University of Birmingham within the UK.

One of the groups recommended the merger might have left behind an enormous, quickly rotating neutron star referred to as a magnetar, which might be powering the gamma ray emission after the preliminary collision. The different three concluded that it almost certainly left behind a black gap, but it surely’s not clear how that might create such a protracted GRB.

“In those few moments between the merger of the neutron stars and the formation of the black hole, there is a big question mark right now,” says Eleonora Troja at Tor Vergata University of Rome. “This is telling us that there is a missing piece of the puzzle that we didn’t even know was missing.”

The lacking piece most likely has to do with the behaviour of the black gap itself, says Troja. “The black hole is like the butler in a crime movie – you know how you watch a crime movie or TV show and the first suspect is always the butler? In astronomy, it’s the black hole, because we know that it has the ability to create things that we do not understand,” says Troja.

While GRB 211211A is by far the most important outlier from the GRB categorisations, it isn’t the one one. Other “oddball” GRBs haven’t been noticed so completely, although, so learning this one will assist us perceive the others. “I’ve been calling this the Rosetta Stone of extended-duration GRBs because it’s letting us connect the physics to the observations in much worse datasets,” says Gompertz. We might have a 3rd class of GRBs for these bizarre occasions, the researchers say.

Journal references: Nature, DOI:10.1038/s41586-022-05327-3, DOI:10.1038/s41586-022-05403-8, DOI:10.1038/s41586-022-05404-7, DOI:10.1038/s41586-022-05390-w; Nature Astronomy, DOI:10.1038/s41550-022-01819-4

Sign as much as our free Launchpad publication for a voyage throughout the galaxy and past, each Friday