AI 中文总结
本研究基于H.E.S.S.观测，通过谱形态学分析等方法，证实银心脊伽马射线谱存在显著曲率，约束了宇宙射线注入特征及相关源的贡献。
AI 中文摘要
从中央分子区（CMZ）探测到的甚高能（VHE）伽马射线辐射，暗示了在银心（GC）附近持续注入的宇宙射线（CR）的扩散传播。利用H.E.S.S.甚高能伽马射线观测数据，我们旨在构建该区域的多分量描述，以推导宇宙射线的空间和谱分布并讨论其潜在起源。我们采用谱形态学分析方法，同时拟合不同分量的谱和空间参数，并结合CMZ与宇宙射线分布的三维描述。假设气体分布模型乘以幂指数为α=1.10±0.05（统计误差）±0.10（系统误差）的1/r^α宇宙射线密度分布，可很好地重现银心脊的辐射。我们未探测到CMZ范围内显著的谱变化，这支持宇宙射线从银心持续注入的观点。我们报告银心脊伽马射线谱存在显著（>3σ）的曲率，这暗示其母质子存在断裂（或截断能量），断裂能量E_b约为15-50 TeV，截断能量E_cut约为60-160 TeV。我们还推导了该区域其他源的最佳拟合谱参数，并报告脉冲星风星云G0.9+0.1的谱存在显著的E≈5 TeV截断。最后，我们将注入源的位置限制在靠近银心处，排除了拱门星团和五重星团作为该辐射的主要贡献者。我们讨论了银心脊辐射的可能起源、导致观测到的曲率的潜在机制、气体成分对HESS J1745-290辐射的可能贡献，并对塑造CMZ的气体云的视线位置给出了定性限制。
英文摘要
Very-high-energy (VHE) $γ$-ray emission detected from the central molecular zone (CMZ) hints at diffusive propagation of cosmic rays (CRs) injected continuously near the Galactic center (GC). Using H.E.S.S. VHE $γ$-ray observations, we aim to construct a multi-component description of the region in order to derive the spatial and spectral distributions of CRs and discuss their potential origin. We rely on a spectro-morphological analysis, in which spectral and spatial parameters of different components are fit simultaneously, and on a three-dimensional description of the CMZ and CR distributions. The GC ridge emission is well reproduced with the assumed gas distribution model weighted by a $1/r^α$ CR density profile with $α= 1.10 \pm 0.05_{\rm{stat}} \pm 0.10_{\rm{syst}}$. We detect no significant spectral variations across the CMZ, which supports a continuous injection from the GC. We report a significant (> 3 $σ$) curvature in the GC ridge $γ$-ray spectrum, implying a parent proton break (or cutoff energy) of $E_b \sim 15-50$ TeV ($E_{\rm{cut}} \sim 60-160$ TeV). We also derive the best-fit spectral parameters of the other sources in the region and report a significant cutoff at $E \sim 5$ TeV in the spectrum of the pulsar wind nebula G0.9+0.1. Finally we constrain the position of the injection site to be close to the GC (ruling out the Arches and Quintuplet clusters as major contributors to the emission). We discuss possible origins for the GC ridge emission, potential mechanisms for causing the observed curvature, a possible contribution of the gas content to the emission of HESS J1745-290 and derive qualitative constraints on the line-of-sight positions of the clouds shaping the CMZ.
CommentsH.E.S.S. Collaboration
