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arXiv 2104.13708astro-ph.HE
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高纬$γ$射线天空中最近Cosmic-Ray加速度的特征

Signatures of Recent Cosmic-Ray Acceleration in the High-Latitude $γ$-Ray Sky

Guðlaugur Jóhannesson, Troy A. Porter

摘要:

宇宙线源在其附近区域的相对论粒子密度暂时高于银河系过去注入活动和传播所积累的背景分布。如果单个源足够接近太阳系,它们的局部增强可能会出现在CR的测量光谱和相关的二次电磁辐射中。在无线电天空中可见的大规模环状结构是这种附近CR源的可能特征。如果是这样的话,这些环在高纬度的$γ$射线天空中也可能有对应的环。使用$\sim$ 10年的数据从费米大面积望远镜,应用贝叶斯分析,包括高斯过程,我们搜索扩展增强发射与推定的附近CR源的能量范围从1 GeV到1 TeV的天空区域$|b| > 30^\circ$。我们仔细控制系统的不确定性,由于星际气体分布的不完善的知识。我们首次确认了Loop~IV是一个$γ$射线辐射源,并在Loop~I中发现了显著的辐射。强有力的证据被发现的银河系$l = 0^\circ$子午线,可能与部分所谓的“费米泡”的不对称功能,和一些证据也被发现$γ$射线发射从其他无线电环路。的CR生产的功能和可能的位置的排放源的影响进行了讨论。

英文摘要:

Cosmic-ray (CR) sources temporarily enhance the relativistic particle density in their vicinity over the background distribution accumulated from the Galaxy-wide past injection activity and propagation. If individual sources are close enough to the solar system, their localised enhancements may present as features in the measured spectra of the CRs and in the associated secondary electromagnetic emissions. Large scale loop like structures visible in the radio sky are possible signatures of such nearby CR sources. If so, these loops may also have counterparts in the high-latitude $γ$-ray sky. Using $\sim$10 years of data from the Fermi Large Area Telescope, applying Bayesian analysis including Gaussian Processes, we search for extended enhanced emission associated with putative nearby CR sources in the energy range from 1 GeV to 1 TeV for the sky region $|b| > 30^\circ$. We carefully control the systematic uncertainty due to imperfect knowledge of the interstellar gas distribution. Radio Loop~IV is identified for the first time as a $γ$-ray emitter and we also find significant emission from Loop~I. Strong evidence is found for asymmetric features about the Galactic $l = 0^\circ$ meridian that may be associated with parts of the so-called "Fermi Bubbles", and some evidence is also found for $γ$-ray emission from other radio loops. Implications for the CRs producing the features and possible locations of the sources of the emissions are discussed.

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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