Large-scale sky surveys require companion large volume simulated mock catalogues. To ensure precision cosmology studies are unbiased, the correlations in these mocks between galaxy properties and their large-scale environments must be realistic. Since galaxies are embedded in dark matter haloes, an important first step is to include such correlations – sometimes called assembly bias – for dark matter haloes. However, galaxy properties correlate with smaller scale physics in haloes which large simulations struggle to resolve. We describe an algorithm that addresses and largely mitigates this problem. Our algorithm exploits the fact that halo assembly bias is unchanged as long as correlations between halo property c and the intermediate-scale tidal environment α are preserved. Therefore, knowledge of α is sufficient to assign small-scale, otherwise unresolved properties to a halo in a way that preserves its large-scale assembly bias accurately. We demonstrate this explicitly for halo internal properties like formation history (concentration c200b), shape c/a, dynamics cv/av, velocity anisotropy β, and angular momentum (spin λ). Our algorithm increases a simulation’s reach in halo mass and number density by an order of magnitude, with improvements in the bias signal as large as 45 per cent for 30-particle haloes, thus significantly reducing the cost of mocks for future weak lensing and redshift space distortion studies.

中文翻译：

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模拟光环目录：使用与本地光环环境的相关性分配未解决的光环属性

大规模的天空调查需要伴随的大量模拟模拟目录。为了确保精确的宇宙学研究是公正的，这些模拟中星系属性与其大尺度环境之间的相关性必须是现实的。由于星系嵌入在暗物质晕中，重要的第一步是包括暗物质晕的这种相关性——有时称为组装偏差。然而，星系特性与光晕中的小尺度物理相关，大型模拟难以解决。我们描述了一种算法，可以解决并在很大程度上缓解这个问题。我们的算法利用了这样一个事实，即只要保留光晕属性 c 和中尺度潮汐环境 α 之间的相关性，光晕组装偏差就不会改变。因此，α的知识足以分配小规模，以一种准确地保持其大规模组装偏差的方式，对光环的其他未解决的属性。我们明确地证明了晕圈内部特性，如形成历史（浓度 c200b）、形状 c/a、动力学 cv/av、速度各向异性 β 和角动量（自旋 λ）。我们的算法将模拟在光晕质量和数量密度方面的范围提高了一个数量级，对于 30 粒子光晕，偏置信号的改进高达 45%，从而显着降低了未来弱透镜和红移空间的模拟成本失真研究。和角动量（自旋λ）。我们的算法将模拟在光晕质量和数量密度方面的范围提高了一个数量级，对于 30 粒子光晕，偏置信号的改进高达 45%，从而显着降低了未来弱透镜和红移空间的模拟成本失真研究。和角动量（自旋λ）。我们的算法将模拟在光晕质量和数量密度方面的范围提高了一个数量级，对于 30 粒子光晕，偏置信号的改进高达 45%，从而显着降低了未来弱透镜和红移空间的模拟成本失真研究。