Astronomers scanning the farthest reaches of space earlier this year spotted something unusual: a powerful signal that lit up in X-ray, optical, and radio bands. The team, from MIT and the University of Birmingham, dubbed the phenomenon AT 2022cmc. They’ve since published a paper showing that AT 2022cmc is a supermassive black hole that has just started a “hyper-feeding frenzy” as it tears apart an enormous star. It’s 8.5 billion light years away, so we don’t exactly have a front-row seat, but we did catch the start of the show.
The signal that led astronomers to the probable black hole is a relativistic jet of material being flung clear of the black hole, known as a tidal disruption event (TDE). This happens when a star wanders too close to a black hole and is devoured. Contrary to popular belief, black holes aren’t constantly vacuuming everything within their gravitational influence. Only matter and light that crosses the event horizon disappear into the singularity. Everything else can be flung clear of the black hole, or as in the case of this TDE, concentrated into a relativistic jet.
The team estimates the jet is composed of matter traveling at 99.99 percent the speed of light, suggesting the black hole is really going to town on this hapless star. First author Dheeraj Pasham of MIT says the black hole is likely consuming about half the mass of the sun every year. Scientists have previously spotted three other Doppler-boosted TDEs in the past—jets that are pointed directly at Earth—but this one is the most distant yet.
This event was initially discovered with an optical sky survey, a first for TDE detection. Follow-ups with the Neutron star Interior Composition ExploreR (NICER), an X-ray telescope on the International Space Station, confirmed something strange was going on. The X-ray source was 100 times more intense than any gamma-ray burst. “AT 2022cmc was so bright and lasted so long, we knew that something truly gargantuan must be powering it – a supermassive black hole,” says co-author Benjamin Gompertz.
Most of the disruption during these events occurs early on, and the team estimates they were able to detect AT 2022cmc within one week of the signal reaching Earth after its 8.5 billion-year journey. The opportunity to study the process from the start could help scientists better understand how black holes produce these high-energy jets. Before AT 2022cmc, it had been over a decade since astronomers spotted a TDE, but the team behind this research hopes that improved technology will reveal more of them in the future.