标题： 利用曲率模拟研究长波长涨落的线性响应 显示英文标题

标题： Linear response to long wavelength fluctuations using curvature simulations

摘要： 我们研究了宇宙学$N$-体模拟中长波长涨落的局域响应，重点关注物质和晕的功率谱、晕丰度以及密度场的非线性变换。 长波长模态通过有效的弯曲宇宙学以及时间与距离的映射来实现。 该方法提供了一种替代的、很可能更精确的方法来测量各向同性的晕偏倚。 局限于线性情况，我们发现由曲率方法得到的偏倚与传统功率谱方法得到的结果在百分之几的水平上总体上一致。 我们也研究了晕计数对场方差变化的响应，并发现密度和方差响应之间的关系斜率与假设普遍质量函数的简单推导相比存在 18% 的差异。 这对利用尺度依赖的偏倚来测量局部非高斯性的幅度具有影响。 我们还分析了晕功率谱和晕-暗物质交叉谱对长波长涨落的响应，并由此得出二阶晕偏倚以及星系功率谱协方差矩阵的超样本方差贡献。 显示英文摘要

摘要： We study the local response to long wavelength fluctuations in cosmological $N$-body simulations, focusing on the matter and halo power spectra, halo abundance and non-linear transformations of the density field. The long wavelength mode is implemented using an effective curved cosmology and a mapping of time and distances. The method provides an alternative, most probably more precise, way to measure the isotropic halo biases. Limiting ourselves to the linear case, we find generally good agreement between the biases obtained from the curvature method and the traditional power spectrum method at the level of a few percent. We also study the response of halo counts to changes in the variance of the field and find that the slope of the relation between the responses to density and variance differs from the naive derivation assuming a universal mass function by 18%. This has implications for measurements of the amplitude of local non-Gaussianity using scale dependent bias. We also analyze the halo power spectrum and halo-dark matter cross-spectrum response to long wavelength fluctuations and derive second order halo bias from it, as well as the super-sample variance contribution to the galaxy power spectrum covariance matrix.