论文标题
深色光环的基于动力学的密度曲线-II。拟合功能
A dynamics-based density profile for dark haloes -- II. Fitting function
论文作者
论文摘要
暗物质光环的密度曲线通常是通过拟合函数（例如NFW或Einasto模型）来描述的，但是这些近似值在过渡区域中分解，在过渡区域中，HAROS因新促进物质而占主导地位。在这里，我们提出了一个简单，准确的新拟合函数，其灵感来自单独的轨道和插入光环组件的渐近形状。轨道术语被描述为截短的einasto曲线，$ρ_{\ rm orb} \ propto \ exp \ exp \ left [-2 /α（r / r _ {\ rm s}）^α-1 /β（r / r / r _ {\ rm t}）半径，以及$α$和$β$，它控制了轮廓陡峭的速度。将插曲曲线模拟为在过度密度中的功率定律，在光晕中心平稳过渡到常数。我们表明，这些公式符合模拟中平均的总概况，在光环质量，红移，宇宙学和增生率的几乎所有膨胀参数空间中，几乎所有膨胀的参数空间的准确性约为5％。固定$α= 0.18 $和$β= 3 $时，该公式将成为一个三参数模型，平均比Einasto概况更好地适合单个光晕。通过与国王剖面的类似，我们表明尖锐的截断类似于结合能的截断。
The density profiles of dark matter haloes are commonly described by fitting functions such as the NFW or Einasto models, but these approximations break down in the transition region where halos become dominated by newly accreting matter. Here we present a simple, accurate new fitting function that is inspired by the asymptotic shapes of the separate orbiting and infalling halo components. The orbiting term is described as a truncated Einasto profile, $ρ_{\rm orb} \propto \exp \left[-2/α (r / r_{\rm s})^α- 1/β (r / r_{\rm t})^β\right]$, with a five-parameter space of normalization, physically distinct scale and truncation radii, and $α$ and $β$, which control how rapidly the profiles steepen. The infalling profile is modelled as a power law in overdensity that smoothly transitions to a constant at the halo centre. We show that these formulae fit the averaged, total profiles in simulations to about 5% accuracy across almost all of an expansive parameter space in halo mass, redshift, cosmology, and accretion rate. When fixing $α= 0.18$ and $β= 3$, the formula becomes a three-parameter model that fits individual halos better than the Einasto profile on average. By analogy with King profiles, we show that the sharp truncation resembles a cut-off in binding energy.
