Astronomers find that most luminous supernova explosions glow in X-rays

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Another member of the new “cow” class supernova explosion has been discovered – the brightest one seen in X-rays to date. The new event, dubbed AT2020mrf, is the fifth so far discovered to belong to a Cow-class supernova. The group is named after the first supernova discovered in this class, AT2018cow, whose name was randomly generated to spell the word “cow”.

What is behind this unusual stellar explosion? New evidence suggests active black holes or neutron star.

When a massive star explodes, it leaves behind a black hole or remnant of a dead star called a neutron star. These stellar remnants are usually relatively inactive and covered in material ejected in the explosion. But according to Yuhan Yao (MS ’20), a Graduated At Caltech, juveniles like cows at their core have highly energetic, mostly exposed compressed bodies that emit high-energy X-ray emissions. Yao is close to presenting the new findings at the 239th meeting of the American Astronomical Society.

“We can see deep inside this explosion to witness firsthand the birth black hole and neutron stars,” he said, noting that supernovae were not covered in matter.

The first cow event, Cow AT2018, surprised astronomers when it was discovered in 2018: a star explosion 10 times brighter at visible light than typical supernovae and fade faster. It also emits a large number of highly variable X-rays, leading astronomers to believe they are directly witnessing the birth of a black hole or neutron star for the first time.

Another differentiating factor for cows is that they remove piles of blocks before they explode, and light them up later, after explosions. When star They explode, generating shock waves that are thought to penetrate the pre-existing material, causing them to glow in light of radio wavelengths and millimeters.

The AT2020mrf is the first to be discovered in X-ray rather than optical light. Yao and his colleagues detected the event in July 2020 using X-ray data from the Russian-German Spectrum-Roentgen-Gamma (SRG) telescope. They examined observations taken in optical light by the Zwicky Transit Facility (ZTF), which operates from Caltech’s Palomar Observatory, and found that ZTF had also observed the event.

The SRG data revealed that this explosion initially illuminated 20 times more X-ray light than the original Cow event. Data retrieved one year later by NASA’s Chandra X-Ray Observatory showed that Explosion Not only is it still hissing but glowing with 200 times more X-ray light than was detected from the original Cow event over the same timeframe.

“When I saw Chandra’s data, I didn’t believe the analysis at first,” Yao said. “I rerun the analysis several times. This is the brightest bovine supernova seen so far in X-rays.”