Astronomers catch a star-devouring black hole in a ‘hyperfeeding frenzy’

Earlier this year, astronomers picked up an unusually bright signal in X-ray, optical and radio regimes, designated AT 2022cmc. They’ve now determined that the most likely source of this signal is a supermassive black hole that devours a star in a “hyper-feeding frenzy” that ejects jets of matter in what’s known as a tidal disruption event (TDE). According to this a new paper Published in the journal Nature Astronomy, it entered the record books: furthest event has yet to be detected roughly 8.5 billion light-years away.

The authors estimate that the jet from this TDE is traveling at 99.99 percent of the speed of light, meaning that the black hole is indeed eating its stellar meal. “It probably swallows up half the mass of the Sun each year” said co-author Dheeraj “DJ” Pasham from the University of Birmingham. “Most of this tidal disruption happens in the early hours, and we were able to capture this event at the very beginning, within a week of the black hole starting to feed off the star.”

as we have previously reportedIt is a popular misconception that black holes behave. like cosmic vacuum cleanersgreedily absorb any substance in their environment. In reality, only things that go beyond the event horizon – including light – are swallowed up and cannot escape, but black holes are also scattered eaters. This means that some of an object’s matter is ejected by a powerful jet.

If this object is a star, the process of breaking up (or “spaghettiizing”) a black hole by strong gravitational forces takes place outside the event horizon, and some of the star’s original mass is violently ejected. This, in turn, can occur a spinning ring of matter (aka a accumulation disk) around the black hole, which emits powerful X-rays and visible light, and sometimes radio waves. Physicist John Wheeler once described sprayed TDEs as “a tube of toothpaste with a tight grip in the middle,” such that matter squirted 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 image After a star was smashed by a black hole 20 million times larger than our Sun in a colliding double galaxy called Arp 299, about 150 million light-years from Earth. A year later, astronomers noted final death throes The image of a star being torn apart by a supermassive black hole called AT 2019qiz provided the first direct evidence that gas ejected during decay and accretion produces the powerful optical and radio emissions previously observed. In January, astronomers identified a second TDE candidate in the radio regime (designated J1533+2727) in archival data collected by the Very Large Array (VLA) telescope in New Mexico.

Astronomers first detected the AT 2022cmc in February and returned promptly multiple telescopes operating in a wide range of wavelengths towards the source. These included an X-ray telescope aboard the International Space Station called the Neutron Star Inner Composition Explorer (NICER). The bright signal, calculated to be equivalent to light from 1,000 trillion suns, was likely to be a gamma-ray burst from the collapse of a massive star. But the data revealed a source 100 times more powerful than even the most powerful gamma-ray burst known.

Our spectrum tells us the weld is hot: about 30,000 degrees, which is typical for TDE. co-author Matt Nicholl said from the University of Birmingham. “But we also saw some light absorption by the galaxy where this event occurred. These absorption lines have shifted considerably towards redder wavelengths, telling us 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 a “period of overaccumulation.” That’s when a swirl of debris forms as the unfortunate star falls into the black hole. But the brightness was still a surprise, given how far the source was from Earth. The authors call this “Doppler reinforcement,” which occurs when the jet points directly at Earth, like how the sound of a passing siren is amplified. The AT 2022cmc is only the fourth Doppler supported TDE ever found; the last one was detected in 2011.

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