发表机构
Konan University（神户女学院大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过三维流体动力学模拟，探究分子云团块性对超新星遗迹前向激波演化的影响，发现团块体积填充因子约10%或更低时，前向激波演化与RX J1713.7-3946的观测一致，且该源的宇宙线质子总能量高于此前估计。
AI 中文摘要
超新星遗迹（SNRs）被广泛认为是银河系宇宙线的主要加速源。近年来，与分子云相互作用的年轻SNRs的详细观测取得了显著进展，典型例子是RX J1713.7-3946。当分子云呈团块状时，其影响不仅会改变辐射特性，还会影响激波的传播。因此，亟需建立观测量与周围介质结构之间的定量联系。本研究通过三维流体动力学模拟，模拟了由超音速湍流驱动的具有非均匀密度结构的分子云及其后续SNR形成过程。为探究不同的超新星前环境，我们通过将阈值数密度以下的气体替换为低密度热气体，系统改变介质的团块性，量化了前向激波速度与高密度团块体积填充因子之间的关系。结果发现，在经历1000年（年轻SNR的典型年龄）时，若团块体积填充因子约为10%或更低，前向激波的演化可与RX J1713.7-3946中测得的快激波速度一致。考虑到强子伽马射线辐射仅源自团块状高密度气体，我们的发现表明，RX J1713.7-3946中宇宙线质子的总能量高于此前估计，至少占典型超新星爆发能量的百分之几。
英文摘要
Supernova remnants (SNRs) are widely considered to be the primary accelerators of Galactic cosmic rays. In recent years, detailed observations have significantly progressed for young SNRs interacting with molecular clouds, a prime example being RX J1713.7-3946. When molecular clouds are clumpy, their impact can affect not only radiation properties but also shock wave propagation. Therefore, a quantitative understanding linking observational quantities with the ambient medium structure is highly required. In this study, we perform three-dimensional hydrodynamic simulations to model a molecular cloud with an inhomogeneous density structure driven by supersonic turbulence and subsequent SNR formation. To investigate various pre-supernova environments, we systematically vary the medium clumpiness by replacing gas below a threshold number density with a low-density hot gas, quantifying the relationship between the forward shock velocity and the volume filling factor of the high-density clumps. As a result, we find that at an elapsed time of 1000 yr-a typical age for a young SNR-the forward shock can evolve consistently with the fast shock velocity measured in RX J1713.7-3946, provided that the clump volume filling factor is approximately 10% or less. Considering that hadronic gamma-ray emission originates exclusively from the clumpy, high-density gas, our findings suggest that the total energy of cosmic-ray protons in RX J1713.7-3946 is higher than previously estimated, amounting to at least a few percent of the typical supernova explosion energy.
Comments11 pages, 12 figures
