Using data collected from the International Space Station (ISS), physicists have been investigating an explosion of X-ray light that originated from a black hole in an outburst phase. The data suggests that during an outburst, black holes consume huge amounts of stellar material and shrink in size by a factor of ten.
The data was gathered from a black hole named MAXI J1820+070 which was detected on March 11, 2018 using the Monitor of All-sky X-ray Image (MAXI) instrument aboard the ISS. The MAXI is an X-ray detection system which monitors for X-ray outbursts like the ones given off by black holes in their outburst phase. “This boomingly bright black hole came on the scene, and it was almost completely unobscured, so we got a very pristine view of what was going on,” Jack Steiner, a research scientist in the Massachusetts Institute of Technology (MIT)’s Kavli Institute for Astrophysics and Space Research, said in a statement.
An outburst is a phase in the evolution of a black hole in which it emits extremely energetic bursts of X-rays while absorbing vast amounts of gas and dust from a nearby star. As the black hole consumes matter, its corona — the highly energized electrons which surround the black hole — shrinks massively from around 100 kilometers in diameter (62 miles) to just 10 kilometers (6.2 miles) in a period of a month.
Once the MAXI instrument observed the outburst, scientists turned to another instrument aboard the ISS, NASA’s Neutron star Interior Composition Explorer (NICER) to obtain more details about the amount and timing of incoming X-ray photons. When a black hole consumes large amounts of matter, this material settles in the accretion disk and generates heat as it spins closer to the black hole. When the material reaches temperatures of millions of degrees, the energy shines out as X-rays.
“This is the first time that we’ve seen this kind of evidence that it’s the corona shrinking during this particular phase of outburst evolution,” Steiner said. “The corona is still pretty mysterious, and we still have a loose understanding of what it is. But we now have evidence that the thing that’s evolving in the system is the structure of the corona itself.”