Understanding the impact of environment on the formation and evolution of dark matter haloes and galaxies is a crucial open problem. Studying statistical correlations in large simulated populations sheds some light on these impacts, but the causal effect of an environment on individual objects is harder to pinpoint. Addressing this, we present a new method for resimulating a single dark matter halo in multiple large-scale environments. In the initial conditions, we ‘splice’ (i.e. insert) the Lagrangian region of a halo into different Gaussian random fields, while enforcing consistency with the statistical properties of Lambda cold dark matter. Applying this technique, we demonstrate that the mass of haloes is primarily determined by the density structure inside their Lagrangian patches, while the haloes’ concentration is more strongly affected by environment. The splicing approach will also allow us to study, for example, the impact of the cosmic web on accretion processes and galaxy quenching.

中文翻译：

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环境对晕质量和浓度的因果影响

了解环境对暗物质晕和星系形成和演化的影响是一个至关重要的开放性问题。研究大型模拟人群中的统计相关性有助于了解这些影响，但环境对单个物体的因果影响更难确定。针对这个问题，我们提出了一种在多个大规模环境中重新模拟单个暗物质晕的新方法。在初始条件下，我们将光晕的拉格朗日区域“拼接”（即插入）到不同的高斯随机场中，同时强制与 Lambda 冷暗物质的统计特性保持一致。应用这种技术，我们证明了光晕的质量主要取决于它们的拉格朗日斑块内的密度结构，而光晕的浓度受环境影响更大。拼接方法还将使我们能够研究，例如，宇宙网对吸积过程和星系淬火的影响。