论文标题
暗物质光环的重生弹性演变，具有差分弹性散射
Gravothermal evolution of dark matter halos with differential elastic scattering
论文作者
论文摘要
我们研究了在具有强度速度和角度依赖性的差异自散射的情况下，暗物质光环的重生进化。我们设计了受控的N体模拟，以模拟Halo中的Rutherford和Moller散射，并遵循其在核心膨胀和循环阶段的进化。模拟显示，常用的转移横截面低估了暗物质自相互作用的效果，但是粘度横截面为对角依赖性暗物质散射进行建模提供了准确的近似。我们研究了光晕的热力学特性，并发现在流体近似下满足了玻尔兹曼方程的三个矩。我们进一步提出了一个恒定的有效横截面，该横截面在光环的特征速度散布与由热传导的动力学理论动机的加权核中整合在一起。有效的横截面为大多数光环演化提供了良好的差异自散射。这表明我们可以在恒定的自相互作用横截面上将天体物理约束映射到具有速度和角度依赖性散射的SIDM模型。
We study gravothermal evolution of dark matter halos in the presence of differential self-scattering that has strong velocity and angular dependencies. We design controlled N-body simulations to model Rutherford and Moller scatterings in the halo, and follow its evolution in both core-expansion and -collapse phases. The simulations show the commonly-used transfer cross section underestimates the effects of dark matter self-interactions, but the viscosity cross section provides an accurate approximation for modeling angular-dependent dark matter scattering. We investigate thermodynamic properties of the halo, and find that the three moments of the Boltzmann equation under the fluid approximation are satisfied. We further propose a constant effective cross section, which integrates over the halo's characteristic velocity dispersion with weighting kernels motivated by kinetic theory of heat conduction. The effective cross section provides a good approximation to differential self-scattering for most of the halo evolution. It indicates that we can map astrophysical constraints on a constant self-interacting cross section to an SIDM model with velocity- and angular-dependent scatterings.
