Supernovae as cosmic ray sources - new study

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Link....<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p><b>NASA: major step toward knowing origin of cosmic rays</b><br /><br /> Outer space is a vast shooting gallery of cosmic rays. Discovered in 1912, cosmic rays are not actually rays at all; they are subatomic particles and ions (such as protons and electrons) that zip through space in all directions at near-light speed, with energies tens of thousands of times greater than particles produced in Earth’s largest particle accelerators. Cosmic rays incessantly bombard Earth, smashing into the atoms and molecules high up in the atmosphere, and producing cascades of secondary particles that reach the surface.<br /><br />Since the 1960s scientists have pointed to supernova remnants — the tattered, gaseous remains of supernovae — as the breeding ground of most cosmic rays. These remnants expand into the surrounding interstellar gas, an energetic interaction that produces a shock front containing magnetic fields that can accelerate charged particles to enormous energies, producing cosmic rays. <br /> /><br />Now, Yasunobu Uchiyama of the Japan Aerospace Exploration Agency (JAXA), and four colleagues, have observed the signature of the shock acceleration of electrons, and demonstrated that magnetic fields in supernova remnants are stronger than previously thought, and are thus fully capable of producing cosmic rays.<br /><br />In a study published in the October 4, 2007, issue of the journal Nature, Uchiyama’s team used Chandra and JAXA’s Suzaku X-ray satellite to look at the northwest edge of supernova remnant RXJ1713.7—3946, located a few thousand light-years from Earth in the constellation Scorpius.<br /><br />With Chandra’s high spatial resolution, the team monitored X-ray hot spots that brightened and faded in less than a year. In particular, a bright hot spot seen in July 2005 was invisible in both July 2000 and May 2006.</p></blockquote> <div class="Discussion_UserSignature"> </div>