The recent discovery of the so-called TeV halos has attracted much attention. The morphology of the emission requires that the region is characterized by severe suppression of the diffusion coefficient. This finding raises many questions as to its origin: (1) is the suppressed diffusion to be attributed to instabilities induced by the same radiating particles? (2) or does it actually show that the diffusion coefficient is small throughout the disk of the Galaxy? In both cases, one would expect that the surroundings of supernova remnants (SNRs) should also show evidence of a reduced diffusion coefficient since most remnants are located in the disk and are expected to be sites of effective particle acceleration. Should we expect the existence of regions of extended γ-ray emission from these regions as well? Here, we investigate the transport of cosmic rays (CRs) that have escaped from SNRs in order to assess the viability of the idea of having a cocoon of suppressed diffusion around them. A comparison of our results with the γ-ray emission from the regions around HB9 and W28 does not provide solid evidence of reduced diffusivity. However, if indeed the phenomenon of reduced diffusivity occurs around SNRs surrounded by molecular clouds, our calculations show that the effects on the grammage of Galactic CRs can be significant.

中文翻译：

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超新星遗迹周围的抑制扩散区域？

最近发现的TeV晕引起了广泛关注。发射的形态要求该区域具有扩散系数严重抑制的特征。这一发现引发了许多关于其起源的问题：（1）抑制扩散是否归因于相同辐射粒子引起的不稳定性？ (2) 或者它实际上表明整个银河系盘面的扩散系数很小？在这两种情况下，人们预计超新星遗迹（SNR）的周围也应该显示出扩散系数降低的证据，因为大多数遗迹位于圆盘中，并且预计是有效粒子加速的场所。我们是否应该预期扩展区域的存在γ- 射线也从这些区域发射？在这里，我们研究了从 SNR 中逸出的宇宙射线 (CR) 的传输，以评估在其周围形成抑制扩散的茧的想法的可行性。我们的结果与γ来自 HB9 和 W28 周围区域的 β 射线发射并没有提供扩散率降低的确凿证据。然而，如果扩散率降低的现象确实发生在分子云包围的信噪比周围，我们的计算表明，这对银河 CR 的克重影响可能很大。