Astrophysicists discover natural particle collider in space
This summer, particle astrophysicists studied a supernova remnant located about 3000 light years away and discovered what is best described as a particle collider in space.
This summer, particle astrophysicists from the Kavli Institute for Particle Astrophysics and Cosmology, along with colleagues from France and Japan, studied a supernova remnant located about 3000 light years away and discovered what is best described as a particle collider in space.
Supernova remnants, giant clouds of dust and gas thrown off by a self-destructing star, are known to accelerate particles. They're one source of the cosmic rays – in reality not rays, but super-accelerated charged particles like protons – that bombard Earth. But when the team analyzed several different observations of the supernova remnant SNR S147, including gamma-ray observations from the LAT instrument on the Fermi Gamma-ray Space Telescope, they discovered something more than accelerating particles.
The researchers saw the accelerated particles smashing into a nearby obstacle, a molecular cloud of dense interstellar gas.
In their paper, the researchers report that the gamma rays from SNR S147 seem to come from the decay of neutral pions, which are produced by the high-energy collisions of two protons, just as sometimes happens at the Large Hadron Collider. In this case, accelerated protons from the supernova remnant collide with relatively slow hydrogen atoms (hydrogen consists of a single proton) in the molecular cloud. The gamma-ray emission is most intense where there are the most hydrogen atom targets.
Physicists cannot study these collisions up-close, as they do using several-story detectors built at collision points in the LHC. However, they can study their effects from afar. These results highlight how gamma-ray observations from the Fermi Gamma-ray Space Telescope are continuing to provide valuable data for understanding particle astrophysics and the fundamental high-energy physics of our universe.
The LAT was designed and built by an international collaboration. SLAC managed the construction and integration of the instrument and KIPAC leads the ongoing operation of the instrument.