标题： 宇宙学尺度上对牛顿引力偏差的星系团集约束 第二部分：功率谱和三阶谱的微扰和数值分析 显示英文标题

标题： Galaxy clustering constraints on deviations from Newtonian gravity at cosmological scales II: Perturbative and numerical analyses of power spectrum and bispectrum

摘要： 我们通过星系的大尺度聚类研究对牛顿引力可能的偏离进行观测约束。 我们测量斯隆数字巡天星系的功率谱和三阶谱，并将其结果与修改引力的经验模型预测进行比较。 我们的模型假设一个额外的类似杨-米尔斯项，有两个参数分别表征修改引力的幅度和长度尺度。 模型预测使用两种方法计算；二阶微扰理论和直接N体模拟。 这些方法使我们能够研究大尺度结构的非线性演化。 利用模拟结果，我们发现微扰理论在修改牛顿模型中对功率谱和三阶谱提供了可靠的估计。 我们还从模拟中构建了模拟星系目录，并推导出对偏离牛顿引力幅度和长度尺度的约束。 功率谱得到的约束与我们早期工作中获得的结果一致，表明修改牛顿模型中引力非线性的先前经验建模是有效的。 如果采用线性偏置，SDSS星系的三阶谱给出的约束与功率谱的约束非常相似。 如果我们允许非线性偏置，则发现二次偏置系数与一次偏置系数的比值b_2/b_1在修改牛顿模型中应满足-0.4 < b_2/b_1 < 0.3。 显示英文摘要

摘要： We explore observational constraints on possible deviations from Newtonian gravity by means of large-scale clustering of galaxies. We measure the power spectrum and the bispectrum of Sloan Digital Sky Survey galaxies and compare the result with predictions in an empirical model of modified gravity. Our model assumes an additional Yukawa-like term with two parameters that characterize the amplitude and the length scale of the modified gravity. The model predictions are calculated using two methods; the second-order perturbation theory and direct N-body simulations. These methods allow us to study non-linear evolution of large-scale structure. Using the simulation results, we find that perturbation theory provides reliable estimates for the power spectrum and the bispectrum in the modified Newtonian model. We also construct mock galaxy catalogues from the simulations, and derive constraints on the amplitude and the length scale of deviations from Newtonian gravity. The resulting constraints from power spectrum are consistent with those obtained in our earlier work, indicating the validity of the previous empirical modeling of gravitational nonlinearity in the modified Newtonian model. If linear biasing is adopted, the bispectrum of the SDSS galaxies yields constraints very similar to those from the power spectrum. If we allow for the nonlinear biasing instead, we find that the ratio of the quadratic to linear biasing coefficients, b_2/b_1, should satisfy -0.4 < b_2/b_1<0.3 in the modified Newtonian model.