论文标题
用星系形状相关性称量中微子
Weighing the Neutrinos with the Galaxy Shape-Shape Correlations
论文作者
论文摘要
星系在早期时期通过各向异性合并过程沿原发性狭窄的细丝形成，并以其形状变得伸长并本质上对齐。宇宙网络的非线性演变通过将它们与多个次要细丝纠缠在一起，从而扩大了主要细丝，从而有减少合并过程的各向异性的作用，因此削弱了后来时期的星系形状形状相关性。假设宇宙网的非线性和复杂性的程度取决于暗物质的性质，我们提出了一个假设，即星系形状形状相关函数$η（r）$，可能是对总中微子质量质量的强大补充探测器，$m_ν$。对高分辨率N体模拟测试该假设，我们表明$m_ν$依赖性$η（r）$ at $ z = 0 $非常敏感，足以区分$m_ν= 0.0 $ ev和$m_ν= 0.1 $ ev。 We also show that the differences in $η(r)$ at $r\le 5\,h^{-1}$Mpc between the models with massless and massive neutrinos cannot be explained by their differences in the small-scale density powers, $σ_{8}$, which implies that the galaxy shape-shape correlation function has a potential to break the notorious cosmic degeneracy between $M_ν$ and $σ_{8} $。
The galaxies form and evolve in the early epochs through the anisotropic merging process along the primary narrow filaments, in the direction of which their shapes become elongated and intrinsically aligned. The nonlinear evolution of the cosmic web broadens the primary filaments, by entangling them with multiple secondary filaments, which has an effect of reducing the anisotropy of the merging process and in consequence weakens the galaxy shape-shape correlations in the later epochs. Assuming that the degree of the nonlinearity and complexity of the cosmic web depends on the nature of dark matter, we propose a hypothesis that the galaxy shape-shape correlation function, $η(r)$, may be a powerful complimentary probe of the total neutrino mass, $M_ν$. Testing this hypothesis against a high resolution N-body simulation, we show that the $M_ν$-dependence of $η(r)$ at $z=0$ is sensitive enough to distinguish between $M_ν=0.0$ eV and $M_ν=0.1$ eV. We also show that the differences in $η(r)$ at $r\le 5\,h^{-1}$Mpc between the models with massless and massive neutrinos cannot be explained by their differences in the small-scale density powers, $σ_{8}$, which implies that the galaxy shape-shape correlation function has a potential to break the notorious cosmic degeneracy between $M_ν$ and $σ_{8}$.
