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Astronomers observe nova explosions with ‘MAGIC’ telescope

The recurrent explosions sent out gamma rays a hundred billion times more energetic than visible light.

(CN) — A team of German astronomers has recorded the gamma radiation from a dramatic explosion deep in space, using two telescopes in Spain.

Roughly 5,000 light-years away from Earth, RS Ophiuchi is a recurrent nova system — a pair of stars in a parasitic relationship. A small and dense white dwarf orbits an old, dying red giant. The red giant "feeds" the white dwarf hydrogen. Every 15 years or so, the white dwarf overheats and erupts in a thermonuclear blast. Then the process repeats itself. The explosion was most recently observed in 2021.

In a paper published Thursday in Nature Astronomy, scientists from the Max Planck Institute for Astronomy in Heidelberg, Germany, detailed how they used the MAGIC (Major Atmospheric Gamma Imaging Cherenkov Telescopes) telescopes system in the Canary Islands to detect gamma rays from the 2021 blast.

"The two MAGIC telescopes recorded gamma rays with the value of 250 gigaelectronvolts (GeV), among the highest energies ever measured in a nova," the institute said in a statement. "By comparison, the radiation is a hundred billion times more energetic than visible light."

Other instruments alerted the MAGIC telescopes to the explosion.

"The spectacular eruption of the RS Ophiuchi shows that the MAGIC telescopes' fast response really pays off: It takes them no more than 30 seconds to move to a new target,"  said David Green, a scientist at the Max Planck Institute for Physics and one of the authors of the paper.  

One of the MAGIC telescopes at the Roque de los Muchachos observatory (Wikipedia)

When RS Ophiuchi's explosion was last seen on earth, on August 8, 2021, it could be seen with the naked eye for about a day. The recurrent nova had been previously observed in February 2006 and five other times since 1898. It is one of seven such systems discovered by astronomers.

The twin MAGIC telescopes are the most sensitive Cherenkov telescopes in the world. They are operated by an international team of about 165 astrophysicists from 24 institutions in 11 different countries. According to the Max Planck Insitute's website, "MAGIC allows astrophysicists to obtain first class data for gaining scientific insights into enigmatic objects and the most violent processes in the universe."


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