Corona of supermassive black hole seen disappearing, reappearing in a remarkable first

For the first time ever, astronomers at Massachusetts Institute of Technology (MIT) and elsewhere have witnessed a supermassive black hole's corona – an ultrabright, billion-degree ring of high energy particles encircling the black hole's event horizon – getting abruptly destroyed.A MIT News report says that while the cause of the dramatic transformation is still unclear, researchers guess that the source of the catastrophe could be a star that got caught in the black hole's gravitational pull.Researchers have speculated that the star could have ricocheted through the black hole's disk of material swirling around it and caused everything in the vicinity to suddenly plummet into the black hole, including its own corona.According to study authors, the phenomenon resulted in a surprising drop in the black hole's brightness, by a factor of 10,000 in a little under a year.[caption id="attachment_8610641" align="alignnone" width="1280"]

Astronomers at MIT and elsewhere watched a black hole’s corona disappear, then reappear, for first time. A colliding star may have triggered the drastic transformation. Image: NASA/JPL-Caltech/MIT[/caption]Erin Kara, assistant professor of physics at MIT, said that usually, changes in luminosity of this intensity are expected to occur over thousands to millions of years."But in this object, we saw it change by 10,000 over a year, and it even changed by a factor of 100 in eight hours, which is just totally unheard of and really mind-boggling,” a report by EurekAlert quoted Kara saying.The wayward star that fell into the supermassive black hole also might have disturbed the magnetic field lines of the black hole's accretion disk, according to the study authors. This disruption is likely why it could no longer support a high-energy corona.Following the corona's disappearance, astronomers reportedly continued watching the black hole as it began slowly pulling together materials from its outer edges to reform its swirling disk.The newly-formed disk then started to emit high-energy X-rays close to the black hole's event horizon, the MIT News report said. In a matter of months, the black hole was able to regenerate its corona.Researchers think the unusual event could offer the astrophysics community clue into how coronas form, and what is needed in a black hole to support one.The study's results were published in The Astrophysical Journal Letters.