标题： 宇宙射线电子物理在宇宙平滑粒子流体动力学模拟中的建模 显示英文标题

标题： Modelling cosmic ray electron physics in cosmological smoothed particle hydrodynamics simulation

摘要： 宇宙射线电子（CRE）的加速和冷却是天体物理学中的重要物理过程。我们开发了一个近似的框架来处理Gadget-3平行平滑粒子流体动力学代码中的CRE物理。在我们的方法中，每个流体单元的CRE谱由一个具有空间变化幅度、上限、下限和谱指数的单个幂律分布来近似。我们认为扩散冲击加速是注入的来源，而相反地，沉降过程归因于同步辐射、逆康普顿散射和库仑散射。我们也包含了绝热增益和损失。我们展示了我们的形式主义对于自由冷却CRE谱的能量和压力能够以$ > 90\%$的精度产生。从我们在宇宙射流模拟中给出的CRE群体计算出的无线电发射的斜率和强度与观测值非常吻合，我们的结果还表明，放松后的星团具有较低的通量。最后，我们研究了CRE过程对宇宙射流模拟的几个影响，我们发现：（1）CRE谱的压力非常小，在射流模拟中可以忽略；（2）CRE过程对射流模拟中气相状态空间的影响可达$3\%$；（3）CRE过程在质量范围$10^{12} -10^{13} h^{-1} M_{\odot}$内对质量函数产生了$5\%$的影响；（4）巨星级星团的气体温度受CRE过程的影响可达$\sim 10\%$。 显示英文摘要

摘要： Cosmic ray electron (CRE) acceleration and cooling are important physical processes in astrophysics. We develop an approximative framework to treat CRE physics in the parallel smoothed particle hydrodynamics code Gadget-3. In our methodology, the CRE spectrum of each fluid element is approximated by a single power-law distribution with spatially varying amplitude, upper cut-off, lower cut-off, and spectral index. We consider diffusive shock acceleration to be the source of injection, and oppositely the sinking processes is attributed to synchrotron radiation, inverse Compton scatters, and Coulomb scatters. The adiabatic gains and losses are also included. We show that our formalism produces the energy and pressure with an accuracy of $ > 90\%$ for a free cooling CRE spectrum. Both slope and intensity of the radio emission computed from the CRE population given by our method in cosmological hydro-simulation coincide well with observations, and our results also show that relaxed clusters have lower fluxes. Finally, we investigate several impacts of the CRE processes on the cosmological hydro-simulation, we find that: (1) the pressure of the CRE spectrum is very small and can be ignored in hydro-simulation, (2) the impacts of the CRE processes on the gas phase-space state of hydro-simulation is up to $3\%$, (3) the CRE processes induce a $5\%$ influence on the mass function in the mass range $10^{12} -10^{13} h^{-1} M_{\odot}$, (4) The gas temperature of massive galaxy cluster is influenced by the CRE processes up to $\sim 10\%$.