Image captures collapse of a supernova

Dunedin citizen scientist and Kilonova Catcher member Peter Jaquiery adjusts the telescope at the...
Dunedin citizen scientist and Kilonova Catcher member Peter Jaquiery adjusts the telescope at the Beverly-Begg Observatory in Dunedin. PHOTO: GREGOR RICHARDSON
A Dunedin astronomer has helped an international group of astronomers pinpoint the core collapse of a supernova in a sector of space "way, way outside our galaxy".

Kilonova Catcher member and citizen scientist Peter Jaquiery said he managed to capture an image of what is called "an afterglow", associated with a core-collapse supernova, in April.

A core-collapse supernova is a cataclysmic explosion that occurs when a massive star, at least eight times the size of our sun, exhausts its nuclear fuel and collapses under its own gravity.

The collapse triggers a shock wave that blasts the star's outer layers into space, leaving behind either a neutron star or a black hole.

The explosion also releases tremendous energy and light, and is a source of heavy elements like gold.

Mr Jaquiery’s image has helped scientists at the Global Rapid Advanced Network Devoted to Multi-messenger Addicts (Grandma), based in France, determine the incident happened about 4.5billion light years away.

He said when a core collapse event occurred, gamma rays were produced.

"So when that gamma ray burst was detected, our group got a message to say that that had happened and I managed to get up to the Dunedin observatory that night and I took a 40-minute image.

"In that image, there was a little group of pixels that I didn't even recognise at the time.

"But I calibrated the image and sent it off to France and they put it through a processing pipeline."

An image of the "afterglow" from a core-collapse supernova (centre of circle), about 4.5 billion...
An image of the "afterglow" from a core-collapse supernova (centre of circle), about 4.5 billion light years away, taken from the Beverly-Begg Observatory in Dunedin. PHOTO: PETER JAQUIERY
Despite the pixels being about 100 million times fainter than the brightest stars in the sky, the organisation pointed large telescopes from around the world in that direction and started taking measurements, he said.

"One of the measurements they made was to measure redshift, which tells us how far away the event was.

"This particular event was about 4.5 billion light years away — way, way outside our galaxy.

"To give you an idea, our nearest galaxy is only a few million light years away.

"To twist it around another way, the universe is thought to be about 13.8 billion years old.

"So the light from this event has been travelling for about a-third of the life of the universe."

Kilonova Catcher allowed members to contribute to tremendous discoveries involving the coalescence of two compact objects (mainly neutron stars) bounded in a compact binary system (BNS).

Mr Jaquiery said studies of violent events like this permitted scientists to have a new perspective of the universe and its mechanisms, including its rate of expansion.

It also helped scientists understand how heavy elements were synthesised and the physics at play in extreme conditions where matter was ultra-condensed.

john.lewis@odt.co.nz

 

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