Using satellite observations, including from ESA’s International Gamma-Ray Astrophysics Laboratory (Integral) mission, and a new developed analytical model, astronomers proved that GRB 221009A — a very bright and long-lasting gamma-ray burst that occurred on October 9, 2022 — deeply impacted on the Earth’s ionospheric conductivity, causing a strong perturbation in the top-side ionosphere (at around 500 km) of our planet. The findings suggests that GRB 221009A — the result of an exploding star almost two billion light-years away — may be amongst the strongest gamma-ray bursts ever detected in the Earth’s atmosphere.
“GRB 221009A was probably the brightest gamma-ray burst we have ever detected,” said Dr. Mirko Piersanti, an astronomer at the University of L’Aquila.
“We’ve been measuring gamma-ray bursts since the 1960s, and this is the strongest ever measured,” said Dr. Pietro Ubertini, an astronomer at the National Institute for Astrophysics.
So strong in fact that its nearest rival on record is ten times weaker. Statistically, a gamma-ray burst as strong as GRB 221009A arrives at Earth only once every 10,000 years.
During the 800 seconds that the gamma rays were impacting, this event delivered enough energy to activate lightning detectors in India.
Instruments in Germany picked up signs that Earth’s ionosphere was disturbed for several hours by the blast.
This extreme amount of energy gave the team the idea to look for the burst’s effects on Earth’s ionosphere.
One of those spacecraft is the China Seismo-Electromagnetic Satellite (CSES), also known as Zhangheng, a Chinese-Italian space mission.
The authors realized that if the gamma-ray burst had created a disturbance, CSES should have seen it. But they could not be sure.
“We had looked for this effect from other gamma-ray bursts in the past but had seen nothing,” Dr. Ubertini said.
In the past, gamma-ray bursts have been spotted affecting the bottom-side ionosphere during…
Read the full article here