Astronomers have noticed a wierd blast of gamma radiation from area that defies categorisation, and it might imply a niche in our understanding of how black holes kind
7 December 2022
A wierd blast of radiation from area might upend how we categorise such flashes, known as gamma ray bursts (GRBs). It appears to come back from a black gap forming surprisingly slowly after two stars merge, indicating a niche in our understanding of black holes.
There are two essential varieties 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 might final minutes and are related to supernovas. However GRB 211211A, noticed in 2021, doesn’t slot in that dichotomy.
4 separate analysis teams noticed the GRB, they usually all noticed the identical factor: it positively got here from two stars colliding, however it lasted about one minute. “Two seconds is how lengthy it takes in a merger for a black gap to kind and eat up all the pieces in its surroundings, so it’s very unusual that this lasted an entire minute,” says Benjamin Gompertz on the College of Birmingham within the UK.
One of many groups urged the merger might have left behind an enormous, quickly rotating neutron star known as a magnetar, which might be powering the gamma ray emission after the preliminary collision. The opposite three concluded that it almost certainly left behind a black gap, however it’s not clear how that might create such an extended GRB.
“In these few moments between the merger of the neutron stars and the formation of the black gap, there’s a massive query mark proper now,” says Eleonora Troja at Tor Vergata College of Rome. “That is telling us that there’s a lacking piece of the puzzle that we didn’t even know was lacking.”
The lacking piece most likely has to do with the behaviour of the black gap itself, says Troja. “The black gap is just like the butler in a criminal offense film – you understand how you watch a criminal offense film or TV present and the primary suspect is all the time the butler? In astronomy, it’s the black gap, as a result of we all know that it has the flexibility to create issues that we don’t perceive,” says Troja.
Whereas GRB 211211A is by far the largest outlier from the GRB categorisations, it isn’t the one one. Different “oddball” GRBs haven’t been noticed so totally, although, so learning this one will assist us perceive the others. “I’ve been calling this the Rosetta Stone of extended-duration GRBs as a result of it’s letting us join the physics to the observations in a lot worse datasets,” says Gompertz. We may 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
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