Nearly a century after their 1912 discovery by Victor Hess the origin of these
energetic particle streaming to us from space remains controversial.
Where in the universe is there an accelerator far more powerful than anything
we can build on Earth? Supernova remnants, young stars, microquasars and even
quasars have been suggested. Thanks to new observational tools progress is
Several people at the High-Energy Astrophyics division are working on different
aspects of the cosmic ray (CR) acceleration problem. In order to work towards
solving the GCR acceleration problem, we are in the process of carrying out
multifrequency observations of turbulent acceleration sites such as powerful
associations of young (OB) stars and 'superbubbles'. We have an active
observational program including radio, mm, sub-mm, X-ray, and TeV gamma-rays,
and collaborate widely with colleagues in the US, Europe and Japan. The
Supernova Remnant group is investigating diffusive shock acceleration in these
remants. process). Supernova remnants (SNRs) have enough energy to power the
cosmic rays and so have long been considered a likely primary source of at
least the less energetic cosmic rays (ie those below "the knee" of the
spectrum, with energies less than 1015 electron volts). Only recently though
have observational evidence has emerged supporting the acceleration of
particles to cosmic ray energies in SNRs by "First-order Fermi shock
acceleration" (also called diffusive shock acceleration), as particles gain
energy by scattering back and forth across the shock.
Daniel Patnaude, Yousaf Butt, Fred Seward, Terrance Gaetz
SN 1006, the remnant of a supernova explosion recorded in CE 1006, is an efficient accelerator of cosmic rays. Its interior is filled with hot X-ray-emitting gas (shown in red), dominated by shocked ejecta material synthesized in the explosion. Along the outer blast wave, however, the X-ray emission is dominated by synchrotron radiation (shown in blue) from electrons with energies in excess of 10 TeV.