Supernova remnant (SNR) shocks provide favourable sites of cosmic ray (CR) proton acceleration if the local magnetic field direction is quasi-parallel to the shock normal. Using the moving-mesh magneto-hydrodynamical (MHD) code AREPO we present a suite of SNR simulations with CR acceleration in the Sedov-Taylor phase that combine different magnetic field topologies, density distributions with gradients and large-scale fluctuations, and -- for our core-collapse SNRs -- a multi-phase interstellar medium with dense clumps with a contrast of $10^4$. Assuming the hadronic gamma-ray emission model for the TeV gamma-ray emission, we find that large-amplitude density fluctuations of $\delta\rho/\rho_0\gtrsim75$ per cent are required to strongly modulate the gamma-ray emissivity in a straw man's model in which the acceleration efficiency is independent of magnetic obliquity. However, this causes strong corrugations of the shock surface that are ruled out by gamma-ray observations. By contrast, magnetic obliquity-dependent acceleration can easily explain the observed variance in gamma-ray morphologies ranging from SN1006 (with a homogeneous magnetic field) to Vela Junior and RX J1713 (with a turbulent field) in a single model that derives from plasma particle-in-cell simulations. Our best-fit model for SN1006 has a large-scale density gradient of $ \nabla{n}\simeq 0.0034~\mathrm{cm}^{-3}~\mathrm{pc}^{-1} $ pointing from south-west to north-east and a magnetic inclination with the plane of the sky of $\lesssim10^\circ$. Our best-fit model for Vela Junior and RX J1713 adopts a combination of turbulent magnetic field and dense clumps to explain their TeV gamma-ray morphologies and moderate shock corrugations.

中文翻译：

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模拟壳型超新​​星遗迹的 TeV 伽马射线形态

如果局部磁场方向与激波法线准平行，超新星遗迹 (SNR) 激波提供了宇宙射线 (CR) 质子加速的有利位置。使用移动网格磁流体动力学 (MHD) 代码 AREPO，我们提出了一套 SNR 模拟，在 Sedov-Taylor 阶段具有 CR 加速，结合了不同的磁场拓扑、密度分布与梯度和大规模波动，以及——对于我们的核心坍缩信噪比——一种多相星际介质，具有密集的团块，对比度为 10^4 美元。假设 TeV 伽马射线发射的强子伽马射线发射模型，我们发现需要 $\delta\rho/\rho_0\gtrsim75$% 的大振幅密度波动来强烈调制伽马射线发射率稻草人' s 模型，其中加速效率与磁倾角无关。然而，这会导致激波表面产生强烈的波纹，伽马射线观测排除了这些波纹。相比之下，磁倾角相关加速度可以很容易地解释从 SN1006（具有均匀磁场）到 Vela Junior 和 RX J1713（具有湍流场）在源自等离子体粒子的单个模型中观察到的伽马射线形态变化- 细胞内模拟。我们最适合 SN1006 的模型具有 $\nabla{n}\simeq 0.0034~\mathrm{cm}^{-3}~\mathrm{pc}^{-1} $ 的大尺度密度梯度，从南方指向-西向东北，与 $\lesssim10^\circ$ 天空平面的磁倾角。