Resolving the Crab pulsar wind nebula at teraelectronvolt energies
Resolving the Crab pulsar wind nebula at teraelectronvolt energies
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DOI：
10.1038/s41550-019-0910-0
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发表时间：
2019-09
期刊：
影响因子：
14.1
通讯作者：
H. Collaboration
中科院分区：
文献类型：
--
作者：
H. Collaboration
蟹状星云是被研究最多的宇宙粒子加速器之一，它在整个电磁光谱中闪耀着明亮的光芒，直到非常高能的伽马射线。从射电到伽马射线光谱部分的观测已经知道，星云是由脉冲星提供动力的，脉冲星将其大部分旋转能量损失转化为高度相对论的外流。这种流出为脉冲星风星云提供动力，该星云的直径可达10光年，充满了相对论电子和正电子。这些粒子在周围磁场中发射同步加速器光子，并通过康普顿向上散射环境中的低能光子产生非常高能量的伽马射线。虽然星云的同步加速器形态已经确定，但还不知道超高能伽马射线是从哪个区域发射出来的，、。在这里，我们报告了蟹状星云在伽马射线能量为52角秒(假设源宽度为高斯型)时的角度延伸，比X射线能量时大得多。这一结果填补了星云多波长覆盖范围的一个缺口，揭示了最高能量伽马射线的发射区。这些伽马射线使我们能够探测到以前无法探测到的电子和正电子能量范围。我们发现，对电磁辐射的模拟重现了我们的测量，为我们对蟹状星云中粒子加速的理解提供了一个不平凡的测试。
The Crab nebula is one of the most-studied cosmic particle accelerators, shining brightly across the entire electromagnetic spectrum up to very-high-energy gamma rays,. It is known from observations in the radio to gamma-ray part of the spectrum that the nebula is powered by a pulsar, which converts most of its rotational energy losses into a highly relativistic outflow. This outflow powers a pulsar wind nebula, a region of up to ten light-years across, filled with relativistic electrons and positrons. These particles emit synchrotron photons in the ambient magnetic field and produce very-high-energy gamma rays by Compton up-scattering of ambient low-energy photons. Although the synchrotron morphology of the nebula is well established, it has not been known from which region the very-high-energy gamma rays are emitted, , , , –. Here we report that the Crab nebula has an angular extension at gamma-ray energies of 52 arcseconds (assuming a Gaussian source width), much larger than at X-ray energies. This result closes a gap in the multi-wavelength coverage of the nebula, revealing the emission region of the highest-energy gamma rays. These gamma rays enable us to probe a previously inaccessible electron and positron energy range. We find that simulations of the electromagnetic emission reproduce our measurement, providing a non-trivial test of our understanding of particle acceleration in the Crab nebula.