C.N. Yang Institute for Theoretical Physics, Department of Physics & Astronomy, Stony Brook University, Stony Brook, New York 11794, USA.
Physics Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
Phys Rev Lett. 2019 Feb 1;122(4):041302. doi: 10.1103/PhysRevLett.122.041302.
Using N-body simulations with massive neutrino density perturbations, we detect the scale-dependent linear halo bias with high significance. This is the first time that this effect is detected in simulations containing neutrino density perturbations on all scales, confirming the same finding from separate universe simulations. The scale dependence is the result of the additional scale in the system, i.e., the massive neutrino free-streaming length, and it persists even if the bias is defined with respect to the cold dark matter plus baryon (instead of total matter) power spectrum. The separate universe approach provides a good model for the scale-dependent linear bias, and the effect is approximately 0.25f_{ν} and 0.43f_{ν} for halos with bias of 1.7 and 3.5, respectively. While the size of the effect is small, it is not insignificant in terms of f_{ν} and should therefore be included to accurately constrain neutrino mass from clustering statistics of biased tracers. More importantly, this feature is a distinct signature of free-streaming particles and cannot be mimicked by other components of the standard cosmological model.
利用包含大量中微子密度涨落的 N 体模拟，我们以高置信度探测到了尺度相关的线性晕族偏置。这是首次在包含所有尺度上中微子密度涨落的模拟中探测到这种效应，证实了来自独立宇宙模拟的相同发现。这种尺度相关性是由于系统中存在额外的尺度，即大量中微子无碰撞输运长度，即使偏置是相对于冷暗物质加重子（而不是总物质）功率谱定义的，这种相关性仍然存在。独立宇宙方法为尺度相关的线性偏置提供了一个很好的模型，对于偏置为 1.7 和 3.5 的晕族，该效应分别约为 0.25f_ν 和 0.43f_ν。虽然这种效应的大小很小，但就 f_ν 而言，它并不是微不足道的，因此应该包括在内，以从有偏示踪剂的聚类统计中准确地约束中微子质量。更重要的是，这个特征是无碰撞输运粒子的独特特征，不能被标准宇宙学模型的其他成分所模拟。
