The GeV-TeV Connection in Galactic ?-Ray Sources
The GeV-TeV Connection in Galactic ?-Ray Sources
复制标题
银河 γ 射线源中的 GeV-TeV 连接
DOI：
10.1086/587129
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Funk S
中科院分区：
文献类型：
--
作者：
Funk S
最近使用大气切伦科夫望远镜系统（如HESS和MAGIC）的观测发现了大量新的非常高能(VHE) γ射线源，从100 GeV到100 TeV，主要集中在银道面。在较低的能量（100 MeV到10 GeV）下，基于卫星的EGRET仪器揭示了沿银河面聚集的一群源。考虑到它们相邻的能带，在两个源星表之间进行系统的相关性研究似乎是合适的。在这里，两个能量域的星系源的种群在观测和现象学的基础上被表征。令人惊讶的是，在位置巧合和光谱一致性方面很少发现常见的源。详细讨论了这些常见源及其潜在对应源和排放机制。在仅在一个能带探测的情况下，首次导出了另一个能带的一致上限。由于与当前VHE仪器的灵敏度不匹配，EGRET的上限相当不受约束。VHE上限对一些EGRET光谱的简单幂律外推有很强的限制，因此强烈建议在10到100 GeV的未探测能量范围内截止。讨论了在GeV和TeV能量下存在截止点和源居群差异的物理原因。最后，对即将到来的GLAST任务中常见的GeV-TeV源进行了预测，首次弥合了当前GeV和TeV仪器之间的能量差距。
Recent observations with atmospheric Cerenkov telescope systems such as HESS and MAGIC have revealed a large number of new sources of very high energy (VHE) γ-rays from 100 GeV to 100 TeV, mostly concentrated along the Galactic plane. At lower energies (100 MeV to 10 GeV) the satellite-based instrument EGRET revealed a population of sources clustering along the Galactic plane. Given their adjacent energy bands, a systematic correlation study between the two source catalogs seems appropriate. Here, the populations of Galactic sources in both energy domains are characterized on observational as well as on phenomenological grounds. Surprisingly few common sources are found in terms of positional coincidence and spectral consistency. These common sources and their potential counterparts and emission mechanisms are discussed in detail. In cases of detection in only one energy band, for the first time consistent upper limits in the other energy band have been derived. The EGRET upper limits are rather unconstraining due to the sensitivity mismatch to current VHE instruments. The VHE upper limits put strong constraints on simple power-law extrapolation of several of the EGRET spectra and thus strongly suggest cutoffs in the unexplored energy range from 10 to 100 GeV. Physical reasons for the existence of cutoffs and for differences in the source population at GeV and TeV energies are discussed. Finally, predictions are derived for common GeV-TeV sources for the upcoming GLAST mission, bridging for the first time the energy gap between current GeV and TeV instruments.