The discovery emission of the extremely energetic light particles was made with data from the telescopes MAGIC and NOT situated on the Canary Islands.  (Photo: NOT, Nordic Optical Telescope/Jyri Näränen)

Scientists detect extreme emission from a far away dying star

Monday 25 Nov 19


Daniele Bjørn Malesani
Transient Data Specialist
DTU Space
Researchers at DTU Space, in an international collaboration with the Niels Bohr Institute, have for the first time determined the emission of extremely energetic light particles during the death of a  heavy star. The discovery is published in the journal Nature.

For the first time emission of extremely energetic particles have coupled with the violent death of a star. The discovery was made in an international collaboration with contributions from researchers at DTU Space and the Niels Bohr Institute at the University of Copenhagen.

"The jet emitted from the gamma ray burst in events like this travels with 99.999 percent of the speed of light"
Daniele Malesani, astrophysicist at DTU Space

The light particles were measured with the telescope MAGIC, situated on the Canary Islands. The researchers subsequently measured the particles with the neighboring NOT (Nordic Optical Telescope). The scientific perspective - the source detection of the emission of particles - is to gain basic insights into the extreme physical processes in the death of the heaviest stars in the universe.

The study is now published in the scientific journal Nature.

When a heavy star dies or collapses, it happens in the form of a supernovae - a gigantic explosion. In about a ten thousandth of the supernovae event it is even more violent.

In these cases the scientists assume that a black hole or an extremely magnetic neutron star is formed. The matter is compressed to form an enormously compact object, spinning extremely fast. The magnetic field along the rotational axis can become intense and emit energetic particles in the direction of the axis in what the researchers names as a jet. This is what can be seen as a so called gamma ray burst.

"The jet emitted from the gamma ray burst in events like this travels with 99.999 percent of the speed of light. And the basic understanding of the most extreme processes in space are at the center of the subsequent research. The discovery of a gamma ray burst also shows us that on this position in the Universe, the conditions for this extreme situation exist. In other words, we can use the gamma ray burst to learn more about these conditions as well," explains DTU Space astrophysicist Daniele Malesani who contributed to the work published in  Nature.

The event happened 4.5 million years ago

The particles, electrons, emitted in the jet, strike light, photons, in their path and transfer the energy to the photons.

The photons travel through the Universe, eventually to be detected and measured on Earth. This gamma ray burst was detected only 29 minutes after its arrival on Earth and the scientists also succeeded in measuring the distance to it. The distance is crucial in order to identify the source and understand the processes emitting a gamma ray burst this energetic into space.

By knowing the distance to the event, the time of the explosion could also be calculated: It took place 4.5 million years ago. This means that this supernovae happened almost simultaneously with the forming of our own sun. Since then, the light from the gamma ray burst has travelled through space and then reached Earth on 14 January 2019. The gamma ray burst took place in the constellation Fornax.

New equipment can improve knowledge of extreme astrophysical events

With a grant from the Carlsberg Foundation a new scientific instrument will added to the Nordic Optical Telescope that would make the distance measurement and positioning of these extreme astrophysical events more efficient in the future.

"Within 5 years, we should become much better at following up on this type of transients or violent, short lived, astrophysical events with The Nordic Optical Telescope. Several research projects are under way, and they should enable us to discover many more of the energetic light particles from dying stars and other extreme objects, in order to be able to study this type of physics in much better detail," says Johan Fynbo from the Cosmic DAWN Center at the Niels Bohr Institute and one of the leading scintists of the work now published in Nature.

(Photo: NOT, Nordic Optical Telescope/Jyri Näränen)

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