Collaborative Research: Toward 3-dimensional, time-dependent, non-LTE radiation transport for cosmological simulations

这个团队将开发一个新的数值方案来跟踪辐射通过星系内部和周围气体的转移。他们将把已经成功解决恒星大气问题的方法与适用于宇宙学模拟的自适应网格细化代码ENZO结合起来。ENZO已提供给社区使用。与以往的辐射输运求解方法不同，该方法采用加速Lambda迭代和短特征法精确地处理散射。将包括Lyman-alpha光子输运中的非lte效应（与局部热力学平衡近似不一致的效应）。辐射将使用算子分裂方法与流体动力学耦合。该代码将用于模拟宇宙历史早期星系间气体的物理状态，因为它被原始恒星和活跃的星系核电离。所有三名团队成员将与研究生一起进行这项研究。ENZO代码是公开的，新的传输解算器将向科学界发布。

This team will develop a new numerical scheme for following the transfer of radiation through the gas within and around galaxies. They will combine methods that have worked successfully in problems of stellar atmospheres with the adaptive mesh refinement code ENZO that is adapted for cosmological simulations. ENZO has been made available for community use. Unlike previous radiation-transport solvers, this new scheme will treat scattering exactly using accelerated Lambda iteration with the short characteristic method. Non-LTE effects (those inconsistent with the approximation of local thermodynamic equilibrium) in the transport of Lyman-alpha photons will be included. Radiation will be coupled to hydrodynamics using an operator-split approach. The code would be used to model the physical state of the gas between the galaxies early is cosmic history, as it is ionized by primeval stars, and by the active nuclei of galaxies. All three of the team members will work with graduate students on this research. The ENZO code is public, and the new transport solver will be released to the scientific community.