Hard X-ray emission of the Earth's atmosphere: Monte Carlo simulations
Hard X-ray emission of the Earth's atmosphere: Monte Carlo simulations
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DOI：
10.1111/j.1365-2966.2007.11746.x
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发表时间：
2006-08
影响因子：
4.8
通讯作者：
S. Sazonov;E. Churazov;R. Sunyaev;M. Revnivtsev
中科院分区：
文献类型：
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作者：
S. Sazonov;E. Churazov;R. Sunyaev;M. Revnivtsev
我们进行蒙特卡罗模拟宇宙射线引起的硬X射线辐射从地球大气层。我们发现，在25-300 keV能量范围内，从大气中出射的宇宙射线谱的形状主要由康普顿散射和光吸收决定，对入射宇宙射线谱几乎不敏感。我们提供了一个拟合公式的硬X射线表面亮度的大气，将由星载仪器测量，作为一个功能的能量，太阳调制水平，地磁截止刚度和天顶角。INTEGRAL天文台最近对地球遮蔽宇宙X射线背景期间大气硬X射线通量的测量与我们的预测在10%以内吻合，这表明地球观测可用于未来硬X射线望远镜的在轨校准。我们还表明，硬X射线光谱产生的宇宙射线在月球，火星和水星的地壳应该是显着不同的地球大气层发射的。
We perform Monte Carlo simulations of cosmic ray-induced hard X-ray radiation from the Earth's atmosphere. We find that the shape of the spectrum emergent from the atmosphere in the energy range 25-300 keV is mainly determined by Compton scatterings and photoabsorption, and is almost insensitive to the incident cosmic ray spectrum. We provide a fitting formula for the hard X-ray surface brightness of the atmosphere as would be measured by a satellite-borne instrument, as a function of energy, solar modulation level, geomagnetic cut-off rigidity and zenith angle. A recent measurement by the INTEGRAL observatory of the atmospheric hard X-ray flux during the occultation of the cosmic X-ray background by the Earth agrees with our prediction within 10 per cent. This suggests that Earth observations could be used for in-orbit calibration of future hard X-ray telescopes. We also demonstrate that the hard X-ray spectra generated by cosmic rays in the crusts of the Moon, Mars and Mercury should be significantly different from that emitted by the Earth's atmosphere.