A compact source of X-rays that sits near the black hole, called the corona, has moved closer to the black hole over a period of just days.
"The corona recently collapsed in towards the black hole, with the result that the black hole's intense gravity pulled all the light down onto its surrounding disk, where material is spiralling inward," said Michael Parker of the Institute of Astronomy in Cambridge, UK, lead author of the research paper.
As the corona shifted closer to the black hole, the gravity of the black hole exerted a stronger tug on the X-rays emitted by it.
Supermassive black holes are thought to reside in the centres of all galaxies. Some are more massive and rotate faster than others.
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The black hole, referred to as Markarian 335, or Mrk 335, is about 324 million light-years from Earth in the direction of the Pegasus constellation.
It is one of the most extreme of the systems for which the mass and spin rate have ever been measured.
Even though some light falls into a supermassive black hole never to be seen again, other high-energy light emanates from both the corona and the surrounding accretion disk of superheated material.
Though astronomers are uncertain of the shape and temperature of coronas, they know that they contain particles that move close to the speed of light.
NASA's Swift satellite has monitored Mrk 335 for years, and recently noted a dramatic change in its X-ray brightness.
This particular energy range offers astronomers a detailed look at what is happening near the event horizon, the region around a black hole from which light can no longer escape gravity's grasp.
The findings appear in the journal Monthly Notices of the Royal Astronomical Society.