Reuters, UK
Nov. 3, 2004

Scientists Close in on Source of Cosmic Rays
Wed 3 November, 2004 18:01

LONDON (Reuters) - An international team of astronomers believe they
have solved a mystery that has been perplexing scientists for 100 years
-- the origin of cosmic rays.

Scientists first discovered the energetic particles that bombard the
Earth nearly a century ago but where they come from has been one of the
big questions in astrophysics.

Using an array of four telescopes in Africa, the scientists produced
the first image showing that the source of cosmic rays could be the
remnant of a supernova, a powerful explosion of a star at the end of
its life.

"This is the first time we were able to take an image of the source,"
David Berge, an astrophysicist at the Max Planck Institute in
Heidelberg, Germany, told Reuters.

Scientists had long thought that supernova explosions were indeed the
source, but did not have evidence to support it, according to Berge,
who reported the findings in the science journal Nature.

He and colleagues from Britain, Armenia, France, Ireland, Namibia,
South Africa and the Czech Republic studied the remnant of a supernova
that exploded about 1,000 years ago and left a shell of debris.

"Because the energy density in cosmic rays is so large, they play an
important role in the development of our galaxy," said Berge.

"We are now at a stage where we seem to be able to prove cosmic rays
come from supernova remnants."

Professor Ian Halliday, head of the Particle Physics and Astronomy
Research Council (PPARC) which funds research, welcomed the findings.

"These results provide the first unequivocal proof that supernovae are
capable of producing large quantities of galactic cosmic rays --
something we have long suspected, but never been able to confirm," he
said in a statement.