The Crab Nebula is one of the brightest sources of high-energy radiation in the sky. In fact, itâs the expanding remains of an exploded star--a supernova. Scientists have used virtually every telescope to study the Crab. The supernova left behind a magnetized neutron star â a pulsar. The pulsar spins 30 times a second. Each rotation sweeps a lighthouse-like beam, creating a pulse of electromagnetic energy detectable across the spectrum.
Recently, NASA's Fermi Gamma Ray Observatory and Italy's AGILE Satellite detected strong gamma-ray flares from the Crab, including a series of "superflares" in April 2011. To help pinpoint the location of these flares, astronomers enlisted NASA's Chandra X-ray Observatory. With its keen X-ray eyes, Chandra saw lots of activity, but none seemed to correlated with the superflare. This hints that whatever is causing the flares is happening about a third of a light year from the pulsar. Chandra observations will likely help scientists explain gamma-ray flares.