COSMIC-RAY ACCELERATION EFFICIENCY VERSUS TEMPERATURE EQUILIBRATION: THE CASE OF SNR 0509-67.5
- Astronomical Institute, Utrecht University, P.O. Box 80000, NL-3508 TA Utrecht (Netherlands)
We study the 0509-67.5 supernova remnant in the Large Magellanic Cloud with the VLT/FORS2 spectrograph. We detect a broad component in the H{alpha} emission with an FWHM of 2680 {+-} 70 km s{sup -1} and 3900 {+-} 800 km s{sup -1} for the southwest (SW) and northeast (NE) shocks, respectively. For the SW, the proton temperature appears to be too low for the shock velocity, which we attribute to a cosmic-ray pressure behind the shock front of at least 20% of the total pressure. For the NE, the post-shock proton temperature and the shock velocity are compatible, only if the plasma behind the shock front has a degree of thermal equilibrium of over 20%, which is at odds with current models for temperature equilibration behind fast shocks, which do not accelerate cosmic rays. If we assume the electron temperature to be less than 10% of the proton temperature, we find a post-shock cosmic-ray pressure of at least 7%.
- OSTI ID:
- 21450965
- Journal Information:
- Astrophysical Journal Letters, Vol. 719, Issue 2; Other Information: DOI: 10.1088/2041-8205/719/2/L140; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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