Astronomers capture a black hole engulfing a star in a ‘hyper-feeding frenzy’

Earlier this year, astronomers detected an unusually bright signal in the X-ray, optical and radio modes, called AT 2022cmc. Now they have found that the most likely source of this signal is a supermassive black hole engulfing a star in a “hyperfeeding frenzy” that shoots out jets of matter in an event known as a tidal disruption event (TDE). according to new paper Published in the journal Nature Astronomy, this is one of the books of records: the the most remote such event yet discovered about 8.5 billion light-years away.

The authors estimate that the jet from this TDE travels at 99.99 percent the speed of light, meaning that the black hole is indeed eating its own stellar food. “It probably absorbs half the mass of the Sun per year.” said co-author Dheeraj “DJ” Pasham University of Birmingham. “Most of this tidal disruption happens early, and we were able to catch this event right at the beginning, within a week of when the black hole started feeding on the star.”

As we have previously reportedthis is a popular misconception about how black holes behave like space vacuum cleaners, they helplessly absorb any issue around them. In reality, only things that pass beyond the event horizon, including light, are absorbed and cannot escape, although black holes eat away. This means that part of the body’s matter is ejected with a powerful jet.

If that object is a star, the black hole’s strong gravitational forces disintegrate (or “spaghetti”) the process beyond the event horizon, and some of the star’s original mass is violently ejected. This in turn can be formed a spinning ring of matter (aka moment storage disk) around a black hole that emits strong X-rays and visible light and sometimes radio waves. Physicist John Wheeler once described sprayed TDEs as “squeezed down the middle of a tube of toothpaste,” with the substance spurting out from both ends. TDEs are one way astronomers can indirectly infer the existence of a black hole.

For example, in 2018, astronomers announced first direct view The results of a star being ripped apart by a black hole 20 million times more massive than our Sun in a pair of colliding galaxies called Arp 299, about 150 million light-years from Earth. A year later, astronomers noted this final death throes AT 2019 has provided the first direct evidence that gas released during the disruption and accretion of a star being torn apart by a supermassive black hole produces strong optical and radio emissions previously observed. In January, astronomers spotted a second TDE candidate (dubbed J1533+2727) in radio mode in archival data collected by the Very Large Array (VLA) telescope in New Mexico.

Astronomers first observed AT 2022cmc in February and immediately turned multiple telescopes operating at wide wavelengths toward the source. These include the Neutron Star Interior Composition Explorer (NICER), an X-ray telescope aboard the International Space Station. Perhaps the bright signal, estimated to be equivalent to the light from 1,000 trillion suns, was a gamma ray burst from the collapse of a giant star. But the data revealed a source 100 times more powerful than even the most powerful gamma rays known.

“Our spectrum tells us that the source is hot: about 30,000 degrees, which is typical of a TDE” said co-author Matt Nicholl University of Birmingham. “But we also saw some light absorption by the galaxy where this event took place. These absorption lines were highly redshifted, indicating that this galaxy is much further away than we expected.”

Given the brightness and longer duration of AT 2022cmc, astronomers concluded that it must be powered by a supermassive black hole. The X-ray data also pointed to an “overaccumulation episode”. That’s when a vortex of debris is created as the unlucky star falls into the black hole. But given how far the source is from Earth, the brightness was still a surprise. The authors call this “Doppler amplification,” which occurs when the jet is pointed directly toward Earth, similar to how the sound of a passing siren is amplified. AT 2022cmc is only the fourth Doppler-enhanced TDE; the last one was discovered in 2011.

DOI: Nature Astronomy, 2022. 10.1038/s41550-022-01820-x (About DOI).