The collision of a dying star with a supermassive black hole results in a spectacular optical flare, which astronomers have discovered.
What occurs when a dying star approaches a supermassive black hole too closely?
Astronomer Igor Andreoni from the University of Maryland (UMD) claims that the following things take place:
The star is initially severely torn apart by the gravitational tidal forces of the black hole, which are stronger than the moon’s influence on Earth’s tides.
The star’s fragments are then gathered into a rapidly rotating disc circling the black hole.
Eventually, what is left of the dying star in the disc is absorbed by the black hole.
A tidal disruption event is what astronomers refer to as this (TDE).
However, the supermassive black hole occasionally releases “relativistic jets” after annihilating a star.
These are material beams moving nearly at the speed of light.
In February 2022, Andreoni and his team made one such discovery during the Zwicky Transient Facility (ZTF) survey.
The sighting was publicly reported by the organisation, and the occasion was given the moniker “AT 2022cmc.”
On November 30, 2022, the team published its findings in the journal Nature.
According to Michael Coughlin, co-leader of the experiment and assistant professor of astronomy at the University of Minnesota Twin Cities, “the last time scientists found one of these jets was well over a decade ago.”
“Based on the data we have, we estimate that just 1% of these damaging events produce relativistic jets, making AT 2022cmc a very uncommon occurrence.
In fact, the event’s dazzling flash is among the brightest ever recorded.
The only two known jetted TDEs prior to AT 2022cmc were found by gamma-ray satellite missions, which find the greatest energy radiation emitted by these jets.
Since the last instance of this was found in 2012, new approaches were needed to find other instances.
Andreoni, a postdoctoral associate in the Department of Astronomy at the University of Maryland and NASA Goddard Space Flight Center, and his group used a cutting-edge, “big picture” strategy to identify AT 2022cmc in order to help fill that requirement.
They made use of generic maps of the sky without particular observational goals, or ground-based optical surveys.
Using ZTF, a wide-field sky survey made by the California-based Samuel Oschin Telescope, The team was able to locate and investigate the otherwise unstudied black hole in a novel way.
Andreoni explained, “We created an open-source data pipeline to store and analyse critical data from the ZTF survey and warn us about anomalous events in real-time.
The ability to quickly identify the TDE with relativistic jets and perform follow-up observations that revealed an exceptionally high luminosity across the electromagnetic spectrum, from the X-rays to the millimetre and radio, was made possible by the quick analysis of ZTF data, which is the equivalent of a million pages of data every night.
The ESO Very Large Telescope indicated that AT 2022cmc was 8.5 billion light years away and that it was fading rapidly based on subsequent observations from other observatories.
The precise location of AT 2022cmc was determined using radio observations from the Very Large Array and optical/infrared photos from the Hubble Space Telescope.
The light from AT 2022cmc outshone it, leading the researchers to conclude that AT 2022cmc was at the centre of a galaxy that was not yet visible. However, future space surveys with the Hubble or James Webb Space Telescopes may reveal the galaxy when the transient ultimately vanishes.
Why certain TDEs appear to launch jets while others do not is still a mystery.
Andreoni and his team deduced from their observations that the black holes in AT 2022cmc and other similarly jetted TDEs are probably spinning quickly in order to drive the incredibly bright jets.
This leads researchers closer to understanding the physics of supermassive black holes at the centres of galaxies billions of light years away by indicating that a rapid black hole spin may be one required component for jet launching.
Astronomy is evolving quickly, according to Andreoni.
A greater number of optical and infrared all-sky surveys are currently underway or will shortly do so.
AT 2022cmc can serve as a guide for researchers as they search for other disruptive events coming from far-off black holes.
Big data mining is therefore more crucial than ever as a technique for expanding our understanding of the universe.
