A supermassive black hole devours a star that has come too close. In extremely rare instances — only about 1% of the time — these so-called tidal disruption events also launch relativistic jets of material moving almost at the speed of light. Astronomers have now detected AT2022cmc, the most distant such event recorded to date.
An artist’s impression of a tidal disruption event. Image credit: Carl Knox / OzGrav, ARC Centre of Excellence for Gravitational Wave Discovery, Swinburne University of Technology.
“Tidal disruption events (TDEs) are bursts of electromagnetic energy that are released when supermassive black holes at the centers of galaxies violently disrupt a star that passes too close,” said University of Maryland astronomer Igor Andreoni and colleagues.
“TDEs provide a window through which to study accretion onto supermassive black holes.”
“In some rare cases, this accretion leads to launching of a relativistic jet, but the necessary conditions are not fully understood.”
On February 11, 2022, the Zwicky Transient Facility (ZTF) detected one of the brightest ever TDEs.
Named AT2022cmc, the event was reminiscent of a gamma ray burst — the most powerful source of light in the Universe.
The prospect of witnessing this rare phenomenon prompted the astronomers to trigger several telescopes from across the globe to observe the mystery source in more detail.
ESO’s Very Large Telescope revealed that AT2022cmc was at a cosmological distance of 8.5 billion light-years away.
The NASA/ESA Hubble Space Telescope optical/infrared images and radio observations from the Very Large Array pinpointed the location of AT2022cmc with extreme precision.
The event is believed to be at the center of a galaxy that is not yet visible because the intense light from the flash still outshines it.
From their observations, the researchers also concluded that the black holes associated with AT2022cmc and other similarly jetted TDEs are likely spinning rapidly.
This suggests that a rapid black hole spin may be one necessary ingredient for jet launching — an idea that brings researchers closer to understanding these mysterious objects at the outer reaches of the Universe.
“We have only seen a handful of these jetted-TDEs and they remain very exotic and poorly understood events,” said Dr. Nial Tanvir, an astronomer at the University of Leicester.
“Astronomy is changing rapidly. More optical and infrared all-sky surveys are now active or will soon come online,” Dr. Andreoni said.
“Scientists can use AT2022cmc as a model for what to look for and find more disruptive events from distant black holes.”
“This means that more than ever, big data mining is an important tool to advance our knowledge of the Universe.”
A paper on the findings was published in the journal Nature.
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I. Andreoni et al. A very luminous jet from the disruption of a star by a massive black hole. Nature, published online November 30, 2022; doi: 10.1038/s41586-022-05465-8
