论文标题
对Geminga Halo的令人困惑的伽马射线频谱的解释
Interpretation of the puzzling gamma-ray spectrum of the Geminga halo
论文作者
论文摘要
由于Geminga PWN释放的电子的缓慢扩散，形成了Geminga周围的伽马射线光环。最新的HAWC和HESS观察结果在Geminga Halo的Tev Gamma-ray频谱中表现出复杂的特征。我们首先表明，新结果无法通过常用的简单模型来解释，其中假定单个幂律注入频谱和$δ= 1/3 $的能量指数为扩散系数。然后，我们提出了一个基于Geminga PWN的X射线观测值的两种人口电子注入模型，该模型由一群新鲜加速的电子群体组成，这些电子从PWN逃脱了通过快速流出和逃脱前PWN内部捕获更长的人群。与单次幂律注入模型相比，两人群模型很好地解释了HAWC和HESS数据，并且拟合优度显着提高。它还可以预测单次幂律模型的伽马射线谱的不同能量依赖性，这可以由Lhaaso在未来的未来进行测试。我们注意到，需要$δ$略大于1的符合HAWC和HESS数据。我们还通过采用两区扩散模型来讨论可能的改进。
The gamma-ray halo around Geminga is formed owing to the slow diffusion of the electrons released by the Geminga PWN. The latest HAWC and HESS observations exhibit complex features in the TeV gamma-ray spectrum of the Geminga halo. We first show that the new results cannot be interpreted by the commonly used simple model, where a single power-law injection spectrum and an energy index of $δ=1/3$ for the diffusion coefficient are assumed. We then propose a two-population electron injection model based on the x-ray observations of the Geminga PWN, which consists of a population of freshly accelerated electrons escaping from the PWN through rapid outflows and a population trapped longer inside the PWN before escaping. The two-population model interprets the HAWC and HESS data well, and the goodness of fit improves significantly compared with the single power-law injection model. It also predicts a different energy dependency of the gamma-ray profile from the single power-law model, which could be tested by LHAASO in the coming future. We note that a $δ$ slightly larger than 1 is needed to fit the HAWC and HESS data consistently. We also discuss the possible improvements by adopting the two-zone diffusion model.
