The light that traveled more than 8.5 billion years to reach us was the dying star’s final gasp before being engulfed by a black hole.
Two different groups of researchers came to the conclusion that AT2022cmc, a mystery sparkle in the sky in February 2022, was the astrophysical jet that blasted from the huge black hole as the shredded star fled beyond its event horizon.
Since AT2022cmc is now the furthest object we have ever observed, it is quite unusual for us to see one of these meals in progress.
The two publications were published in Nature and Nature Astronomy, respectively.
“The last time scientists discovered one of these jets was well over a decade ago,” says astronomer Michael Coughlin of the University of Minnesota Twin Cities in the US.
“From the data we have, we can estimate that relativistic jets are launched in only 1 percent of these destructive events, making AT2022cmc an extremely rare occurrence. In fact, the luminous flash from the event is among the brightest ever observed.”
In our chaotic universe, there is a lot happening. Many of these encounters and events, such as supernovae, fast radio bursts, stellar collisions, interactions in compact binaries, and black hole feeding frenzy, are unpredictable, spewing out transient flares of light that blaze across the depths of space before dissipating.
We can only see the brightness of these enormous but fleeting cosmic events by carefully scanning wide areas of the sky.
Such a flare was captured at the Zwicky Transient Facility in February. In the moments that followed, 20 other telescopes on Earth and in space went into action and began collecting data on the rapid flame.
A team of researchers lead by Coughlin and the astronomer Igor Andreoni of the University of Maryland came to the conclusion that the event was caused by a tidal disruption event as a consequence of the abundance of data available. The offender? a fast rotating, half a Sun every year, 500 million times more massive than the Sun supermassive black hole that is consuming star material.
Extreme occurrences called tidal disruption events happen when a star travels just a little bit too near to a black hole. The star is pulled so forcefully by the tidal forces in the gravitational field of that black hole that it is ripped apart. The star fragment then hits the black hole.
When this happens, a light flare is created. If the flare is strong enough, we can see it from Earth, but it eventually fades away.
The light that astronomers saw from AT2022cmc was not caused by that.
“Things looked pretty normal the first three days. Then we looked at it with an X-ray telescope, and what we found was, the source was too bright,” says astronomer Dheeraj Pasham of MIT, who led the second paper.
“This particular event was 100 times more powerful than the most powerful gamma-ray burst afterglow. It was something extraordinary.”
An astrophysical jet was the source of the light, according to analysis. Not all of the material that is whirling about a black hole as it feeds always makes it over the event horizon.
Particles are released from the black hole’s poles at speeds that are almost equal to the speed of light by material that is channeled along magnetic field lines that are just outside the event horizon.
One of those jets, in the instance of AT2022cmc, is aimed directly at us and moving at 99.999% the speed of light. Near-light-speed motion causes a shift in the frequency of the light’s wavelength, which causes the material to look brighter than it really is. Relativistic beaming, often known as Doppler boosting, is the term used to describe this phenomenon.
Only four Doppler-boosted tidal disruption events have ever been identified, including AT2022cmc.
Scientists believe that we may get a great deal of knowledge from this fading light from more than half the universe distant. For instance, it is unclear why some tidal disruption occurrences have jets while others do not. The black hole’s quick spin might play a key role in the development of jets.
Additionally, it is not known how supermassive black holes develop and form. High feeding rates, as those seen by the AT2022cmc black hole, may be able to explain the situation.
Using an optical scan, the incident was also the first jetting tidal disturbance event to be discovered. Future astronomers will be able to identify more of them because to the vast amounts of data that have been gathered.
“Astronomy is changing rapidly,” Andreoni says.
“More optical and infrared all-sky surveys are now active or will soon come online. 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.”
The study was published in the journals Nature and Nature Astronomy.
