The biggest cosmic explosion ever, right


April 13, 2023

(Nanowerk News) The location of the brightest cosmic explosion ever recorded has been determined at a distance of 2.4 billion light years from Earth by a team of astronomers.

The explosion, known as a gamma-ray burst (GRB), was first picked up by the sensors of the veteran spacecraft Voyager last October, arriving on Earth only 19 hours later.

It was later detected by several gamma-ray space telescopes, such as NASA’s Swift and Fermi, and the European Space Agency’s INTEGRAL.

But two papers published this week suggest that spectroscopic data collected by the European Southern Observatory’s (ESO) Very Large Telescope may finally help pinpoint the origin of the explosion in a previously unknown galaxy.

“Initial reports suggest that (the explosion) may even have come from within our own Milky Way galaxy,” said Dr Tayyaba Zafar, from Australian Astronomical Optics (AAO) Macquarie University, an author of the paper describing the discovery. “But we can measure distances accurately because we have spectroscopic, as well as infrared and optical, data from ESO.”

Scientists believe the explosion was so bright because it is relatively close and because the radiation beam is aimed at us.

It is also detected for a very long time. Gamma-ray bursts can last from milliseconds to several hours, but this one, called GRB221009A, can be observed for 10 hours.

There was also no sign of a supernova, which is usually expected with an explosion of that size.

“With something this big, you’d think it must be a star that died in an explosion at the end of its life,” said Dr Zafar. “We now think it must collapse in on itself to become a black hole.”

Although this is the brightest gamma-ray burst visible from Earth in the 55 years since the first gamma-ray satellite was placed in orbit, Dr Zafar’s team, led by Dr Daniele Bjørn Malesani of Radboud University in the Netherlands, believe an explosion of this size is possible. occurs every 1000 years or so.

The paper identifying the explosion site involved 42 scientists from 30 research institutes around the world. It was peer reviewed and accepted for publication in the journal Astronomy & Astrophysics (“Brightest GRB ever detected: GRB 221009A as very bright event at z=0.151”).

The second paper by a team led by Andrew Levan, from Radboud University, which also includes Dr Zafar, looked at the explosion at longer wavelengths using the James Webb Space Telescope (JWST). Combining the ESO spectrum analysis with the JWST data allows an in-depth investigation of the nature of this explosion. It will be published in Astrophysics Journal Letter(“First JWST spectrum of GRB flare: No bright supernova in the brightest GRB observation of all time, GRB 221009A”).

This activity has spawned at least 11 papers published in Astrophysics Journal Letterrepresents a broad global collaboration involving dozens of scientists.

Dr Zafar is internationally renowned as an expert on the effect of dust on light as it travels through space.

“For both studies, I modeled the dust’s effect on the GRB spectrum and how its light is extinguished as it passes through our galaxy,” he said.


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