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تسجيل مستخدم جديدX-ray Hotspot Flares and Implications for Cosmic Ray Acceleration and Magnetic Field amplification in Supernova Remnants
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For more than fifty years, it has been believed that cosmic ray (CR) nuclei are accelerated to high energies in the rapidly expanding shockwaves created by powerful supernova explosions. Yet observational proof of this conjecture is still lacking. Recently, Uchiyama and collaborators reported the detection of small-scale X-ray flares in one such supernova remnant, dubbed RX J1713-3946 (a.k.a. G347.3-0.5), which also emits very energetic, TeV (10^12 eV) range, gamma-rays. They contend that the variability of these X-ray hotspots implies that the magnetic field in the remnant is about a hundred times larger than normally assumed; and this, they say, means that the detected TeV range photons were produced in energetic nuclear interactions, providing a strong argument for acceleration of protons and nuclei to energies of 1 PeV (10^15 eV) and beyond in young supernova remnants. We point out here that the existing multiwavelength data on this object certainly do not support such conclusions. Though intriguing, the small-scale X-ray flares are not the long sought-after smoking gun of nucleonic CR acceleration in SNRs.
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Supernova remnants (SNRs) are believed to accelerate particles up to high energies through the mechanism of diffusive shock acceleration (DSA). Except for direct plasma simulations, all modeling efforts must rely on a given form of the diffusion coef
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