February 14, 2013
The Mysterious Origin Of Cosmic Rays
[ Watch the Video: Fermi Proves Supernova Remnants Produce Cosmic Rays ]
Lee Rannals for redOrbit.com - Your Universe OnlineA thousand-year-old supernova has given the European Space Observatory's Very Large Telescope (VLT) ample opportunity to gain some clues about the origins of cosmic rays.
The new observations, reported in the journal Science today, suggest the presence of fast-moving particles in the supernova remnant.
Over a thousand years ago, in 1006 AD, a new star was seen in the southern skies, shining brighter than Venus and rivaling the brightness of the Moon. Astronomers have recently identified the phenomenon that took place then as a supernova named SN 1006. They also found a glowing and expanding ring of material in the southern constellation of Lupus.
These supernova remnants may also be where some cosmic rays are formed, but, until now, the details of how this could have occurred have remained a mystery.
Astronomers using the VLT looked at the SN 1006 remnant in more detail than ever, studying what is happening where high-speed material ejected by the supernova is rushing into the stationary interstellar matter. This high-velocity shock front is similar to the sonic boom produced by an aircraft going supersonic, and is a natural candidate for a cosmic particle accelerator.
“This is the first time we were able to take a detailed look at what is happening in and around a supernova shock front," said Sladjana NikoliÄ, from Max Planck Institute for Astronomy, Heidelberg, Germany. "We found evidence that there is a region that is being heated in just the way one would expect if there were protons carrying away energy from directly behind the shock front.”
Not only did the team obtain information about the shock material, but they also were able to build a map of the properties of the gas, and how these properties change across the shock front.
The team said the findings were surprising, suggesting that there were many very rapidly moving protons in the gas in the shock region. While these are not the sought-for high-energy cosmic rays, they could be necessary "seed particles."
“This kind of novel observational approach could well be the key to solving the puzzle of how cosmic rays are produced in supernova remnants," said co-author Glenn van de Ven of the Max Planck Institute for Astronomy.
Astronomers were able to be the first to use an integral field spectrograph to probe the properties of the shock fronts of supernova remnants. This isn't the only study recently published that scientists used supernova to help unveil more about the mysteries of our universe.
Last week, scientists reported in the journal Nature about how they used supernovae observations to help make better forecasts for the cosmic events. They wrote about how they observed an energetic outburst from a supernova called SN 2010mc, witnessing a large mass-loss event about a month before the explosion.
Discovering SN 2010mc showed the team that they were able to mark the imminent death of a massive star, helping them to predict the explosion to catch a supernova in the act.