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arXiv 2108.01738astro-ph.HE
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用H.E.S.S搜索巨分子云中增强的TeV gamma-ray发射

Search for enhanced TeV gamma-ray emission from Giant Molecular Clouds using H.E.S.S

A. Sinha, V. Baghmanyan, G. Peron, Y. Gallant, S. Casanova, M. Holler, A. Mitchell

摘要:

宇宙射线(CR)与巨分子云(GMC)内的致密气体相互作用产生中性π介子,后者又衰变为伽马射线。因此,GMC的γ射线辐射是宇宙射线密度和云内物质密度的直接示踪剂。GMCs增强TeV发射的检测,即,一个发射明显大于预期的平均银河宇宙射线照射云,可能意味着在本地宇宙射线密度的变化,由于,例如,最近的加速器在云附近的存在。这样的伽马射线观测对于探测银河系中的宇宙射线分布至关重要,但使用当代成像大气切伦科夫望远镜(IACTs)执行起来很复杂。这些研究需要区分强宇宙线诱导背景、大尺度漫发射和来自云的发射,这对于当前一代IACT的小视场来说是困难的。在本文中,我们使用H.E.S.S.收集了超过16年的数据,以寻找我们银河系内分子半乳糖中心环中GMCs的TeV发射。我们实现了一个3D的FoV似然技术,并同时模拟强子背景,银河漫发射和预期从已知的VHE源探测过量TeV的伽马射线发射GMCs的发射。

英文摘要:

Cosmic Ray (CR) interactions with the dense gas inside Giant Molecular Clouds (GMCs) produce neutral pions, which in turn decay into gamma rays. Thus, the gamma ray emission from GMCs is a direct tracer of the cosmic ray density and the matter density inside the clouds. Detection of enhanced TeV emission from GMCs, i.e., an emission significantly larger than what is expected from the average Galactic cosmic rays illuminating the cloud, can imply a variation in the local cosmic ray density, due to, for example, the presence of a recent accelerator in proximity to the cloud. Such gamma-ray observations can be crucial in probing the cosmic ray distribution across our Galaxy, but are complicated to perform with present generation Imaging Atmospheric Cherenkov Telescopes (IACTs). These studies require differentiating between the strong cosmic-ray induced background, the large scale diffuse emission, and the emission from the clouds, which is difficult to the small field of view of present generation IACTs. In this contribution, we use H.E.S.S. data collected over 16 years to search for TeV emission from GMCs in the inner molecular galacto-centric ring of our Galaxy. We implement a 3D FoV likelihood technique, and simultaneously model the hadronic background, the galactic diffuse emission and the emission expected from known VHE sources to probe for excess TeV gamma ray emission from GMCs.

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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