In 2018, astronomers took the first-ever picture of a black hole, a fascinating and unprecedented glimpse of an event horizon.
And as it turns out, the black hole -- dubbed M87* and located some 55 million light-years away -- also let out a massive belch of gamma rays while scientists from the Event Horizon Telescope team, an international collaboration combining data from sensors around the globe, were getting a closer look.
The campaign gathered data from 25 terrestrial and orbital telescopes in April 2018, and scientists are still poring over the results.
"We were lucky to detect a gamma-ray flare from M87 during this Event Horizon Telescope's multi-wavelength campaign," said University of Trieste Giacomo Principe, coauthor of a new paper accepted for publication in the journal Astronomy & Astrophysics, in a statement. "This marks the first gamma-ray flaring event observed in this source in over a decade, allowing us to precisely constrain the size of the region responsible for the observed gamma-ray emission."
The team is hoping the gamma ray outburst data will help scientists study the "physics surrounding M87's supermassive black hole," according to Principe.
The researchers found that the outburst, an energetic flare releasing copious amounts of high-energy radiation, absolutely dwarfed the black hole itself, extending beyond its event horizon by tens of millions of times.
The blast lasted for roughly three Earth days, covering an area roughly 170 times the distance from the Sun to the Earth.
Scientists believe the flare is the result of material consumed by the black hole interacting with its external magnetic field.
Explosions of this type are some of the most violent in the universe but are infamously hard to capture as they are usually only visible in specific wavelengths.
"The activity of this supermassive black hole is highly unpredictable -- it is hard to forecast when a flare will occur," said coauthor and Nagoya City University researcher Kazuhiro Hada in a statement.
The team found that the "flare region has a complex structure and exhibits different characteristics depending on the wavelength," according to University of Tokyo astroparticle physicist and team member Daniel Mazin.
It was such a violent event that even the overall ring structure of the black hole itself appeared to change in relation to the flare, suggesting an intriguing relationship between the two.
But there's still a lot we don't understand about the nature of these massive celestial objects.
"How and where particles are accelerated in supermassive black hole jets is a longstanding mystery," said coauthor and University of Amsterdam professor Sera Markoff. "For the first time, we can combine direct imaging of the near event horizon regions during gamma-ray flares from particle acceleration events and test theories about the flare origins."