Extremely Fast Acceleration of Cosmic Rays in a Supernova Remnant
Galactic cosmic rays (CRs) are widely believed to be accelerated by shock waves associated with the expansion of supernova ejecta into the interstellar medium. A key issue in this long-standing conjecture is a theoretical prediction that the interstellar magnetic field can be substantially amplified at the shock of a young supernova remnant (SNR) through magnetohydrodynamic waves generated by cosmic rays. Here we report a discovery of the brightening and decay of X-ray hot spots in the shell of theSNRRXJ1713.723946 on a one-year timescale. This rapid variability shows that the X-rays are produced by ultrarelativistic electrons through a synchrotron process and that electron acceleration does indeed take place in a strongly magnetized environment, indicating amplification of the magnetic field by a factor of more than 100. The X-ray variability also implies that we have witnessed the ongoing shock-acceleration of electrons in real time. Independently, broadband X-ray spectrometric measurements of RXJ1713.723946 indicate that electron acceleration proceeds in the most effective ('Bohm-diffusion') regime. Taken together, these two results provide a strong argument for acceleration of protons and nuclei to energies of 1 PeV (1015 eV) and beyond in young supernova remnants.
- ISBN 10 : OCLC:727205550
- Judul : Extremely Fast Acceleration of Cosmic Rays in a Supernova Remnant
- Pengarang : ,
- Bahasa : en
- Tahun : 2007
- Halaman : 0
- Google Book : http://books.google.com/books?id=BZeJAQAACAAJ&dq=intitle:Supernova&hl=&source=gbs_api
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Ketersediaan :
Galactic cosmic rays (CRs) are widely believed to be accelerated by shock waves associated with the expansion of supernova ejecta into the interstellar medium.