Helder E A, Vink J, Bassa C G, Bamba A, Bleeker J A M, Funk S, Ghavamian P, van der Heyden K J, Verbunt F, Yamazaki R
Astronomical Institute Utrecht, Utrecht University, Post Office Box 80000, NL-3508 TA Utrecht, Netherlands.
Science. 2009 Aug 7;325(5941):719-22. doi: 10.1126/science.1173383. Epub 2009 Jun 25.
Cosmic rays are the most energetic particles arriving at Earth. Although most of them are thought to be accelerated by supernova remnants, the details of the acceleration process and its efficiency are not well determined. Here we show that the pressure induced by cosmic rays exceeds the thermal pressure behind the northeast shock of the supernova remnant RCW 86, where the x-ray emission is dominated by synchrotron radiation from ultrarelativistic electrons. We determined the cosmic-ray content from the thermal Doppler broadening measured with optical spectroscopy, combined with a proper-motion study in x-rays. The measured postshock proton temperature, in combination with the shock velocity, does not agree with standard shock heating, implying that >50% of the postshock pressure is produced by cosmic rays.
宇宙射线是抵达地球的能量最高的粒子。尽管大多数宇宙射线被认为是由超新星遗迹加速的，但加速过程的细节及其效率尚未完全确定。在这里，我们表明宇宙射线所产生的压力超过了超新星遗迹 RCW 86 东北激波后的热压力，在该区域，X 射线发射主要由超相对论电子的同步辐射主导。我们通过光学光谱测量的热多普勒展宽，并结合 X 射线的自行研究，确定了宇宙射线的含量。测量得到的激波后质子温度与激波速度相结合，与标准激波加热不一致，这意味着激波后压力的 50%以上是由宇宙射线产生的。
