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arXiv 2409.13010astro-ph.COastro-ph.GA
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宇宙丝对暗物质晕的因果效应

The causal effect of cosmic filaments on dark matter halos

Lund Observatory, Division of Astrophysics, Department of Physics(隆德天文台);Sub-department of Astrophysics, University of Oxford(牛津大学天体物理学子部门);Institut d’Astrophysique de Paris, UMR 7095, CNRS, and Sorbonne Université(巴黎天体物理学研究所);Max-Planck Institute for Astrophysics(马克斯·普朗克天体物理学研究所);Kavli IPMU (WPI), UTIAS, The University of Tokyo(东京大学)

Anatole Storck, Corentin Cadiou, Oscar Agertz, Daniela Galárraga-Espinosa

AI总结:

本文研究了宇宙丝对暗物质晕形成非线性效应,发现晕的自转和形状受环境影响显著,这对宇宙 shear 调查的建模有重要影响。

摘要:

大规模宇宙环境如何影响银河系性质尚不明确。暗物质晕最初遵循线性理论演化,其后续演化由晕区域及外部环境的非线性结构形成驱动。本文首次明确控制晕的线性演化部分,揭示了非线性效应在晕形成中的作用。我们专注于近邻大规模宇宙丝的影响,通过拼接方法固定晕形成初期的密度、速度和势场,同时改变其外部环境。在银河系质量晕范围内,发现其质量和virial半径不受环境剧烈变化影响,而自转和相对于大质量丝的形状方向则显著受扰,波动可达均值的80%。结果表明,晕的取向和形状无法仅通过初始条件的局部分析准确预测。这对欧几里得等宇宙shear调查的内在对齐建模有直接影响。结果强调,非线性与大尺度环境的耦合可能与线性效应幅度相当,应在暗物质晕形成分析模型中明确考虑。

英文摘要:

The way in which the large-scale cosmic environment affects galactic properties is not yet understood. Dark matter halos, which embed galaxies, initially evolve following linear theory. Their subsequent evolution is driven by non-linear structure formation in the halo region and in its outer environment. In this work, we present the first study where we explicitly control the linear part of the evolution of the halo, thus revealing the role of non-linear effects on halo formation. We focus specifically on the effect of proximity to a large cosmological filament. We employ the splicing method to keep fixed the initial density, velocity, and potential fields where a halo will form while changing its outer environment, from an isolated state to one where the halo is near a large filament. In the regime of Milky Way-mass halos, we find that mass and virial radius of such halos are not affected by even drastic changes of environment, whereas halo spin and shape orientation with respect to a massive filament is largely impacted, with fluctuations of up to 80 % around the mean value. Our results suggest that halo orientation and shape cannot be predicted accurately from a local analysis in the initial conditions alone. This has direct consequences on the modeling of intrinsic alignment for cosmic shear surveys, like Euclid. Our results highlight that non-linear couplings to the large-scale environment may have an amplitude comparable to linear effects, and should thus be treated explicitly in analytical models of dark matter halo formation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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