A Weird Gamma-Ray Burst Has Been Spotted, And It's Coming From a Rare Collapsar - ScienceAlert

This was SN 1998bw, the very first collapsar supernova to be observed, emitted by a massive stellar core undergoing gravitational collapse, and the very first supernova to be associated with a gamma-ray burst.

Now, astronomers have detected a new gamma-ray burst, and it's the shortest we've ever detected in association with a collapsar.

GRB 200826A, detected in August 2020, was thought to be a different kind of gamma-ray burst, known as a short gamma-ray burst - such as those emitted by a compact binary merger, like two neutron stars.

Gamma-ray bursts are thought to be associated with relativistic jets - that is, jets of plasma blasting out at a significant percentage of the speed of light in a vacuum - launched by the newly formed black hole as it accretes material.

In addition, the discovery suggests that many events classified as short gamma-ray bursts may actually be misclassified long gamma-ray bursts - that is, we thought we were looking at neutron star mergers, but they're actually hypernovae with hindered jets.