No evidence for gamma-ray halos around active galactic nuclei resulting from intergalactic magnetic fields
No evidence for gamma-ray halos around active galactic nuclei resulting from intergalactic magnetic fields
复制标题
没有证据表明活跃星系核周围存在由星系际磁场产生的伽马射线晕
DOI：
10.1051/0004-6361/201015892
复制
发表时间：
2010
影响因子：
6.5
通讯作者：
I. Tkachev
中科院分区：
文献类型：
--
作者：
A. Neronov;D. Semikoz;P. Tinyakov;I. Tkachev
我们分析了Ap. J. Lett.中报道的堆积活动星系核周围的伽马射线晕，2010，722，L39。首先，我们表明，周围的堆叠活动星系核的γ射线的角分布是一致的蟹状星云脉冲星，这是费米/LAT的点源周围的γ射线的角分布。这使得它不太可能晕是由电磁级联TeV光子在星系际空间。然后，我们比较周围的堆叠活动星系核与费米/LAT的点扩散函数（PSF）的伽马射线的角分布，并确认存在一个多余的PSF以上。然而，我们证明，这种效果的幅度和角度大小是不同的费米/LAT仪器的前部和后部转换的光子，因此是一种仪器效应。
We analyze the gamma-ray halo around stacked AGNs reported in Ap.J.Lett., 2010, 722, L39. First, we show that the angular distribution of gamma-rays around the stacked AGNs is consistent with the angular distribution of the gamma-rays around the Crab pulsar, which is a point source for Fermi/LAT. This makes it unlikely that the halo is caused by an electromagnetic cascade of TeV photons in the intergalactic space. We then compare the angular distribution of gamma-rays around the stacked AGNs with the point-spread function (PSF) of Fermi/LAT and confirm the existence of an excess above the PSF. However, we demonstrate that the magnitude and the angular size of this effect is different for photons converted in the front and back parts of the Fermi/LAT instrument, and thus is an instrumental effect.