Super-bright supernova brings rare gamma-ray burst

A long-lasting gamma-ray burst has been observed after a super-bright supernova – a very unusual event.

On the rare occasions gamma-ray bursts have been observed with supernovae they usually only last a few minutes, but this one lasted more than half an hour.

The supernova itself was more than three times as bright as the supernovae previously associated with gamma-ray bursts.

The results are published by scientists from the Niels Bohr Institute in the scientific journal, Nature.

Researchers have observed several long gamma-ray bursts lasting over a half an hour, but they had not yet been able to connect them with a supernova.

When a massive star dies, the core collapses into a neutron star that revolves very quickly and forms an extremely intense magnetic field. Such objects are called magnetars – a class of neutron stars that were first discovered by Chryssa Kouveliotou, who is a close collaborator with the gamma-ray burst group at the Dark Cosmology Centre at Niels Bohr Institute, which she frequently visits.

“A magnetar has a magnetic field that is in the realm of a billiard (1,000,000,000,000,000) times stronger than the Earth’s magnetic field,” explains Johan Fynbo, a professor at the Dark Cosmology Centre at the Niels Bohr Institute at the University of Copenhagen.

“At the same time, these bizarre magnetars rotate several times per second and this is a gigantic reservoir of energy, which can facilitate a huge explosion, resulting in a particularly bright supernova and an extreme burst of gamma radiation, which is what we observe,” he said.

The light from the supernova has travelled 6.4 billion years before it arrived at the Earth, so the incident took place about 7.3 billion years after the Big Bang.