New clues to birthplace of cosmic rays
doi:10.1038/nindia.2011.29 Published online 28 February 2011
Earth-bound powerful radio telescopes have helped astrophysicists provide new clues about the elusive nature of ultrahigh-energy cosmic rays (UHECRs) emanating from a supernova located in the spiral galaxy NGC3278, about 130 million light years away.
There is a limit on how far cosmic rays can travel through space. The Greisen–Zatsepin–Kuzmin (GZK) limit states that cosmic rays above a certain energy (6 × 1019 eV) will interact with cosmic microwave background photons and can journey through space for around 150 million light years. So far, 69 cosmic rays have been detected with energies beyond the GZK limit.
To explain such cosmic rays, the researchers studied the size-magnetic field evolution of the supernova SN 2009bb using the US-based Very Large Array and the India-based Giant Metrewave Radio Telescope. The study clearly shows that SN 2009bb can confine UHECRs and accelerate them to the highest energies seen experimentally.
On earth, accelerated charged particles are made to collide with each other in very large particle accelerators such as the Large Hadron Collider at CERN to study the fundamental laws of nature. "These UHECRs possess energies many orders of magnitude larger than the accelerated particles at the LHC, making them important for studying and revealing how the laws of nature might emerge at even higher energies," says Alak Ray, one of the researchers.
The authors of this work are from: the Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai, India, Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA, and the Department of Physics, Royal Military College of Canada, Kingston, Ontario, Canada.