The overwhelming foreground causes severe contamination on the detection of 21 cm signal during the Epoch of Reionization (EoR). Among various foreground components, the Galactic free–free emission is less studied, so that its impact on the EoR observation remains unclear. To better constrain this emission, we perform Monte Carlo simulation of H α emission, which comprises direct and scattered H α radiation from H ii regions and warm ionized medium (WIM). The positions and radii of H ii regions are quoted from the Wide-Field Infrared Survey Explorer H ii catalog, and the WIM is described by an axisymmetric model. The scattering is off dust and free electrons that are realized by applying an exponential fitting to the HI4PI H i map and an exponential disk model, respectively. The simulated H α intensity, the Simfast21 software, and the latest SKA1-Low lay...

中文翻译：

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EoR前景模型的银河自由发射的蒙特卡罗实现

在电离时代（EoR）期间，压倒性前景对21 cm信号的检测造成严重污染。在各种前景成分中，对银河自由发射的研究较少，因此其对EoR观测的影响尚不清楚。为了更好地限制这种发射，我们对Hα发射进行了蒙特卡洛模拟，其中包括来自H ii地区和热电离介质（WIM）的直接和散射Hα辐射。H ii区域的位置和半径是从“宽视野红外测量浏览器H ii”目录中引用的，而WIM由轴对称模型描述。灰尘和自由电子的散射是通过分别对HI4PI H i图和指数盘模型应用指数拟合实现的。Simfast21软件模拟的Hα强度，