标题： 用重子物理和惰性中微子暗物质解决大到不能倒的问题 显示英文标题

标题： Addressing the too big to fail problem with baryon physics and sterile neutrino dark matter

摘要： N体暗物质模拟在$\Lambda$冷暗物质模型中结构形成的预测表明，银河系晕中存在一群亚晕，其核心密度高于对银河系卫星推断的密度，这种矛盾被称为“太大而无法失败”问题。 提出的解决方案包括重子效应、银河系晕质量更小以及温暗物质。 我们使用一个半解析的星系形成模型来生成银河系晕类似物卫星群体的光度函数，结果随后与Jiang和van den Bosch的亚晕剥离模型结合，以预测10个最亮卫星的亚晕$V_\mathrm{max}$函数。 我们发现，选择最亮的卫星（而非最质量大的）以及在早期建模超新星排出气体会增加生成观测到的银河系卫星$V_\mathrm{max}$函数的可能性。 首选的晕质量是$6\times10^{11}M_{\odot}$，它有14%的概率容纳像银河系卫星那样的$V_\mathrm{max}$函数。 对于$1.0\times10^{12}M_{\odot}$晕，这个概率降低到8%，而对于$1.4\times10^{12}M_{\odot}$晕，这个概率降低到3%。 我们得出结论，银河系卫星$V_\mathrm{max}$函数与CDM宇宙学相容，如Sawala等人之前通过流体动力学模拟所发现的。无菌中微子-温暖暗物质模型与观测结果的吻合度更高，生成观测到的银河系卫星$V_\mathrm{max}$函数的可能性最大为35%。然而，需要更多的工作来检查在无菌中微子宇宙学中半解析剥离模型是否校准正确，并检查我们的无菌中微子模型是否产生足够数量的暗淡卫星。 显示英文摘要

摘要： N-body dark matter simulations of structure formation in the $\Lambda$CDM model predict a population of subhalos within Galactic halos that have higher central densities than inferred for satellites of the Milky Way, a tension known as the `too big to fail' problem. Proposed solutions include baryonic effects, a smaller mass for the Milky Way halo, and warm dark matter. We test these three possibilities using a semi-analytic model of galaxy formation to generate luminosity functions for Milky Way halo-analogue satellite populations, the results of which are then coupled to the Jiang & van den Bosch model of subhalo stripping to predict the subhalo $V_\mathrm{max}$ functions for the 10 brightest satellites. We find that selecting the brightest satellites (as opposed to the most massive) and modelling the expulsion of gas by supernovae at early times increases the likelihood of generating the observed Milky Way satellite $V_\mathrm{max}$ function. The preferred halo mass is $6\times10^{11}M_{\odot}$, which has a 14 percent probability to host a $V_\mathrm{max}$ function like that of the Milky Way satellites. This probability is reduced to 8 percent for a $1.0\times10^{12}M_{\odot}$ halo and to 3 percent for a $1.4\times10^{12}M_{\odot}$ halo. We conclude that the Milky Way satellite $V_\mathrm{max}$ function is compatible with a CDM cosmology, as previously found by Sawala et al. using hydrodynamic simulations. Sterile neutrino-warm dark matter models achieve a higher degree of agreement with the observations, with a maximum 35 percent chance of generating the observed Milky Way satellite $V_\mathrm{max}$ function. However, more work is required to check that the semi-analytic stripping model is calibrated correctly in the sterile neutrino cosmology, and to check if our sterile neutrino models produce sufficient numbers of faint satellites.