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arXiv 1302.6460astro-ph.HEastro-ph.COhep-ph
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宇宙对伽马射线的透明度

Transparency of the Universe to gamma rays

Alessandro De Angelis, Giorgio Galanti, Marco Roncadelli

摘要:

利用最新的河外背景光和射电背景观测资料,对红移z_s < 3的源,我们计算了10 GeV < E_0 < 10^13 GeV范围内观测到的γ射线光子的能量E_0,使得由此得到的光学深度τ_gamma(E_0,z_s)取1,2,3和4.6,对应于观测到的通量变暗,分别为e^-1 = 0.37、e^-2 = 0.14、e^-3 = 0.05和e^-4.6 = 0.01。在源距D = 8 kpc以下,我们发现对于任意的E_0值,τ_gamma(E_0,DH_0/c)< 1。在局域宇宙(z_s = 0)的极限情况下,我们将所得结果与Coppi和Aharonian在1997年导出的结果进行了比较。目前的成就对于计划中的地面探测器,如CTA、HAWC和HiSCORE具有极其重要的意义。

英文摘要:

Using the most recent observational data concerning the Extragalactic Background Light and the Radio Background, for a source at a redshift z_s < 3 we compute the energy E_0 of an observed gamma-ray photon in the range 10 GeV < E_0 < 10^13 GeV such that the resulting optical depth tau_gamma(E_0,z_s) takes the values 1, 2, 3 and 4.6, corresponding to an observed flux dimming of e^-1 = 0.37, e^-2 = 0.14, e^-3 = 0.05 and e^-4.6 = 0.01, respectively. Below a source distance D = 8 kpc we find that tau_gamma(E_0,DH_0/c) < 1 for any value of E_0. In the limiting case of a local Universe (z_s = 0) we compare our result with the one derived in 1997 by Coppi and Aharonian. The present achievement is of paramount relevance for the planned ground-based detectors like CTA, HAWC and HiSCORE.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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