Gamma ray bursts are produced by some of the most energetic objects in the Universe, such as stars collapsing into supernovae. NASA's Swift observatory is designed to catch these rare events as they unfold, with hardware and software that detect sudden spikes in high-energy photons and respond by pointing the main hardware at their source. In March of this year, a somewhat unusual object set off the observatory's gamma ray trigger, and then did something that the scientists running the hardware called "unheard of"—it set it off three more times in less than 48 hours.
Normally, things catch the Swift's attention by exploding, which is a one-time-only event, so the multiple triggering was already unusual. But looking through previous sweeps of the region showed that the source, called Sw 1644+57, was already present several days before setting off the trigger, and the source continued to emit prodigious X-rays for more than two weeks afterward. Also unusual was the variability of the emissions; the X-ray flux varied by a factor of two on timescales as short as 100 seconds. Running the numbers on an unprecedented event
But the truly eye-popping figures came when researchers calculated the amount of energy released by Sw 1644+57. The brightest X-ray flare they detected pumped out over 1048ergs/second, and the total output during the first 11 days is estimated at over 1053ergs. For those of you not up on your ergs, that's over 1030 megatons or, as the authors put it, "equivalent to ~10% of the rest energy of the Sun."
