Largest X-Ray Flares Ever Detected Remain Mysterious

NASA's Chandra X-ray Observatory recently detected an incredibly powerful flare of x-rays from the supermassive black hole that's at the center of our Milky Way galaxy, raising some serious questions about the behavior of this black hole, and how it influences the immense world that it plays host to.

Chandra is not exactly a stranger to powerful and unexpected flares coming from the center of the Milky Way. Back in 2012, the x-ray detecting telescope managed to pick up signs of an unusually powerful flare coming straight from "Sagittarius A*," the mysterious center of the Milky Way suspected to be the home of a black hole 4.5 million times the mass of our Sun.

Then on Sept. 13, 2013, the observatory detected another flare, this one three times brighter than the previous flare and 400 times brighter than usual. Now NASA supports that earlier last year, in October, Chandra picked up another "megaflare" of x-rays, this one 200 times brighter than usual x-ray emissions.

It remains unclear exactly what's going on here, but now experts are far more certain that these flares are not just data anomalies or mere coincidence; they are a consistently occurring phenomenon that was utterly unaccounted for.

Researchers are scrambling to explain these events, looking at what was occuring around Sagittarius A just before the galaxy lit up with x-ray emissions.

"The bottom line is the jury is still out on what's causing these giant flares from Sgr A*," astronomical investigator Gabriele Ponti, of the Max Planck Institute for Astrophysics in Garching, Germany, said in a statement. "Such rare and extreme events give us a unique chance to use a mere trickle of infalling matter to understand the physics of one of the most bizarre objects in our galaxy."

According to Ponti and his colleagues, there are two leading theories to explain this phenomenon. The first is that large, but unlucky asteroids simply got too close to the supermassive black hole.

"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," explained researcher Fred Baganoff of the Massachusetts Institute of Technology in Cambridge, Massachusetts. "That's just how long we saw the brightest X-ray flare last, so that is an intriguing clue for us to consider."

A second theory concerns tangling magnetic field lines, where the reshuffling of magnetism within a black hole could potentially create a burst of radiation.

These results were recently presented at the 225th meeting of the American Astronomical Society being held in Seattle, but Ponti is quick to add that we are nowhere near fully understanding the phenomenon. After all, we aren't even sure if black holes are real.

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