Record-breaking gamma-ray burst may be the most powerful explosion ever recorded

In the early morning hours of today, October 14, 2022, astronomers using the Gemini South Telescope in Chile operated by NSF’s NOIRLab observed the unprecedented aftermath of one of the most powerful explosions ever recorded, Gamma-Ray Burst GRB221009A. This record-breaking event, which was first detected on Oct. 9, 2022, by orbiting X-ray and gamma-ray telescopes, occurred 2.4 billion light-years from Earth and was likely triggered by a supernova explosion giving rise to a black hole.

A titanic cosmic explosion has sparked an explosion of activity among astronomers around the world as they rush to study the aftermath of what is one of the closest and possibly most energetic gamma-ray bursts (GRBs) never observed. Recently published observations by two independent teams using the Gemini South telescope in Chile, one of the Gemini International Observatory’s twin telescopes operated by NSF’s NOIRLab, targeted the bright, glowing remnants of the explosion, which likely heralded a supernova giving rise to a black hole.

The GRB, identified as GRB 221009A, occurred about 2.4 billion light-years away in the direction of the constellation Sagitta. It was first detected on the morning of October 9 by space X-ray and gamma-ray telescopes, including NASA’s Fermi Gamma-ray Space Telescope, the Neil Gehrels Swift Observatory and the Wind spacecraft.

As news of this detection spread rapidly, two teams of astronomers worked closely with Gemini South personnel to obtain the earliest possible observations of the afterglow of this historic explosion.

In the early morning hours of Friday, October 14, two Rapid Target of Opportunity imagery observations were conducted by two independent teams of observers led by graduate students Brendan O’Connor (University of Maryland/George Washington University) and Jillian Rastinejad (Northwestern University). The sightings took place within minutes of each other. The first observation used the FLAMINGOS-2 instrument, a near infrared imaging spectrograph. The other observation used the Gemini Multi-Object Spectrograph (GMOS).

Teams now have access to both datasets for their analyzes of this energetic and evolving event.

“The exceptionally long GRB 221009A is the brightest GRB on record and its afterglow is breaking all records at all wavelengths,” O’Connor said. “Because this burst is so bright and so close, we believe this is a once-in-a-century opportunity to address some of the most fundamental questions about these outbursts, from black hole formation to testing models of dark matter. .”

Through the quick reaction of observers and staff, combined with the use of the Gemini Director’s discretionary time and effective data reduction software like Gemini’s “FIRE” DRAGONS (Fast Initial Reduction Engine), this image was quickly produced shortly after the sightings.

“The agility and responsiveness of Gemini’s infrastructure and personnel are hallmarks of our observatory and have made our telescopes invaluable resources for astronomers studying transient events,” said Gemini Chief Scientist Janice Lee. .

Already, communications have been sent to other astronomers via NASA’s gamma-ray coordinate network, whose archives are now filling up with reports of the whole world. Astronomers believe it represents the collapse of a star several times the mass of our Sun, which in turn launches an extremely powerful supernova and gives rise to a black hole 2.4 billion light-years away. Earth.

“In our research group, we call this burst the ‘BOAT,’ or brightest ever, because when you look at the thousands of bursts that gamma-ray telescopes have detected since the 1990s, this one stands out. .,” Rastinejad said. “Gemini’s sensitivity and diverse instrument range will help us observe the optical counterparts of GRB221009A much later than most ground-based telescopes can observe. It will help us understand what did it. gamma burst so particularly bright and energetic.”

When black holes shape, they drive powerful jets of particles that are accelerated almost to the speed of light. These jets then shoot through what remains of the progenitor star, emitting X-rays and gamma rays as they propagate through space. If these jets are directed in the general direction of the Earth, they are observed as bright flashes of X-rays and gamma rays.

Another one gamma ray burst this brilliant may not appear for decades or even centuries and the case is still evolving. It should be noted other extraordinary reports of disturbances of the earth’s ionosphere affecting longwave radio transmissions of energetic radiation from event GRB221009A. Scientists also wonder how very high energy photons of 18 TeV (tera-electron-volt) observed with China’s Great High Altitude Air Shower Observatory could defy our standard understanding of physics and survive their 2.4 billion year journey to Earth.

This event, because of its relative proximity to the Earth, is also a unique opportunity to better understand the origin of the elements heavier than iron and if they all come only neutron star mergers or also the collapse of stars that trigger GRBs.

“The Gemini observations will allow us to make maximum use of this near event and search for signatures of heavy elements formed and ejected during the star’s massive collapse,” O’Connor said.

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Provided by NOIRLab