论文标题
恒星飞溅：簇内灯的边缘
Stellar splashback: the edge of the intracluster light
论文作者
论文摘要
我们检查了C-Eagle模拟中星系簇的郊区，以量化恒星和暗物质分布的“边缘”。暗物质中最陡峭的斜率的半径（通常用作飞溅半径的代理）位于〜r_200m；此功能的强度和位置取决于最近的质量积聚率，与以前的工作非常吻合。有趣的是，恒星分布（或簇内光，ICL）也具有明确的边缘，这与光环的飞溅半径直接相关。因此，检测ICL的边缘可以提供对光环的物理边界的独立度量，以及最近的质量积聚率。我们表明，这些苛性碱也可以在预测的密度曲线中看到，但是必须注意考虑子结构和其他非扩散材料的影响，这可能会偏向和/或削弱最陡峭的斜率信号。这对于恒星材料尤其重要，恒星材料在subhaloes中的分数高于暗物质。 Finally, we show that the `stellar splashback' feature is located beyond current observational constraints on the ICL, but these large projected distances (>> 1 Mpc) and low surface brightnesses (mu >> 32 mag/arcsec^2) can be reached with upcoming observational facilities such as the Vera C. Rubin Observatory, the Nancy Grace Roman Space Telescope, and Euclid.
We examine the outskirts of galaxy clusters in the C-EAGLE simulations to quantify the `edges' of the stellar and dark matter distribution. The radius of the steepest slope in the dark matter, commonly used as a proxy for the splashback radius, is located at ~r_200m; the strength and location of this feature depends on the recent mass accretion rate, in good agreement with previous work. Interestingly, the stellar distribution (or intracluster light, ICL) also has a well-defined edge, which is directly related to the splashback radius of the halo. Thus, detecting the edge of the ICL can provide an independent measure of the physical boundary of the halo, and the recent mass accretion rate. We show that these caustics can also be seen in the projected density profiles, but care must be taken to account for the influence of substructures and other non-diffuse material, which can bias and/or weaken the signal of the steepest slope. This is particularly important for the stellar material, which has a higher fraction bound in subhaloes than the dark matter. Finally, we show that the `stellar splashback' feature is located beyond current observational constraints on the ICL, but these large projected distances (>> 1 Mpc) and low surface brightnesses (mu >> 32 mag/arcsec^2) can be reached with upcoming observational facilities such as the Vera C. Rubin Observatory, the Nancy Grace Roman Space Telescope, and Euclid.
