Photos: NASA Fermi Spots 'Superflares' in Crab Nebula (PHOTOS)
By IB Times Staff Reporter | May 12, 2011 09:58 AM EDT
The Crab Nebula supernova remnant unleashed a surprisingly enormous blast of gamma rays, the highest-energy light in the universe. The superflare was detected by NASA's Fermi Gamma-ray Space Telescope on April 12 and lasted six days.
The outburst was similar to an enormous 'superflare' five times more powerful than any flare previously seen from the object. The nebula, which is the wreckage of an exploded star whose light reached Earth in 1054, is one of the most studied objects in the sky. The Crab Nebula is composed mainly of the dusty remain of an exploded star.
"At the heart of an expanding gas cloud lies what's left of the original star's core, a superdense neutron star that spins 30 times a second. With each rotation, the star swings intense beams of radiation toward Earth, creating the pulsed emission characteristic of spinning neutron stars (also known as pulsars)," NASA said in a statement.
The flares occur as the intense magnetic field near the pulsar undergoes sudden restructuring, the scientisits expect. Such changes can accelerate particles like electrons to velocities near the speed of light. As these high-speed electrons interact with the magnetic field, they emit gamma rays in a process known as synchrotron emission.
Scientists say that to account for the observed emission the electrons must have energies 100 times greater than can be achieved in any particle accelerator on Earth. This makes them the highest-energy electrons known to be associated with any cosmic source.
Scientists estimate that the size of the emitting region must be comparable in size to the solar system, based on the rise and fall of gamma rays during the April outbursts. If circular, the region must be smaller than roughly twice Pluto's average distance from the sun.
Take a look at some of the pictures of Crab Nebula supernova remnant from NASA's Fermi Gamma-ray Space Telescope:
A Hubble visible light image of the Crab Nebula inset against a full-sky gamma ray map showing the location of the nebula (croshairs).
Source: NASA
Scientists hoped that NASA's Chandra X-ray Observatory would locate X-ray sources correlated to the gamma-ray flares seen by Fermi and Italy's AGILE satellites. Two observations were made during the April 2011 superflare, but there's no clear evidence of them in the Chandra images.
Source: NASA
Fermi's LAT discovered a gamma-ray 'superflare' from the Crab Nebula on April 12, 2011. These images show the number of gamma rays with energies greater than 100 million electron volts from a region of the sky centered on the Crab Nebula. Both views eliminate emission form the Crab pulsar by showing the sky in between its pulses. In both images, the bright source below is the Geminga pulsar. At left, the region 20 days before the flare; at right, April 14.
Source: NASA
There are strange goings-on in the Crab Nebula. On April 12, 2011, NASA's Fermi Gamma-ray Space Telescope detected the most powerful in a series of gamma-ray flares occurring somewhere within the supernova remnant.
Source: NASA
There are strange goings-on in the Crab Nebula. On April 12, 2011, NASA's Fermi Gamma-ray Space Telescope detected the most powerful in a series of gamma-ray flares occurring somewhere within the supernova remnant.
Source: NASA
Artist interpretation of Crab supernova.
Source: NASA
This view of the Crab Nebula in visible light comes from the Hubble Space Telescope and spans 12 light-years. The supernova remnant, located 6,500 light-years away in the constellation Taurus, is among the best-studied objects in the sky.
Source: NASA
