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Newswise AMHERST, Mass.Last September, after years of watching, a team of scientists led by Amherst College astronomy professor Daryl Haggard observed and recorded the largest-ever flare in X-rays from a supermassive black hole at the center of the Milky Way. The astronomical event, which was detected by NASAs Chandra X-ray Observatory, puts the scientific community one step closer to understanding the nature and behavior of supermassive black holes.

Haggard and her colleagues discussed the flare today at a press conference during this years meeting of the American Astronomical Society in Seattle.

Supermassive black holes are the largest of black holes, and all large galaxies have one. The one at the center of our galaxy, the Milky Way, is called Sagittarius A* (or, Sgr A*, as it is called), and scientists estimate that it contains about four and a half million times the mass of our Sun.

Scientists working with Chandra have observed Sgr A* repeatedly since the telescope was launched into space in 1999. Haggard and fellow astronomers were originally using Chandra to see if Sgr A* would consume parts of a cloud of gas, known as G2.

Unfortunately, the G2 gas cloud didnt produce the fireworks we were hoping for when it got close to Sgr A*, she said. However, nature often surprises us and we saw something else that was really exciting.

Haggard and her team detected an X-ray outburst last September that was 400 times brighter than the usual X-ray output from Sgr A*. This megaflare was nearly three times brighter than the previous record holder that was seen in early 2012. A second enormous X-ray flare, 200 times brighter than Sgr A* in its quiet state, was observed with Chandra on October 20, 2014.

Haggard and her team have two main ideas about what could be causing Sgr A* to erupt in this extreme way. One hypothesis is that the gravity of the supermassive black hole has torn apart a couple of asteroids that wandered too close. The debris from such a tidal disruption would become very hot and produce X-rays before disappearing forever across the black holes point of no return (called the event horizon).

If an asteroid was torn apart, it would go around the black hole for a couple of hours like water circling an open drain before falling in, said colleague and co-principal investigator Fred Baganoff of the Massachusetts Institute of Technology in Cambridge, MA. Thats just how long we saw the brightest X-ray flare last, so that is an intriguing clue for us to consider.

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Amherst College Astronomy Professor Detects Record-Breaking Black Hole Outburst