发表机构
Argelander-Institut für Astronomie; Michigan State University; University of Geneva（阿尔加兰德天文研究所; 密歇根州立大学; 日内瓦大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用TNG、EAGLE和SIMBA模拟，分析宇宙晕内与星系间介质的重子预算，提出闭合半径、补偿半径等特征尺度，揭示重子分布偏离暗物质及反馈对大尺度结构的影响。
AI 中文摘要
对本地宇宙的观测表明，除质量最大的星系团外，晕内的重子比例低于宇宙平均值。这一亏损可利用先前建立的闭合半径来表征，即晕心距离，在该距离内所包围的重子比例达到宇宙平均值。利用TNG、EAGLE和SIMBA模拟，我们研究了重子与暗物质分布何时、如何以及在何种尺度上发生偏离。在z=0时，不到30%的宇宙重子位于宿主星系晕内，而暗物质约为45%，超过70%的重子留在星系间介质（IGM）中。在闭合半径的基础上，我们引入了另外三个特征尺度：补偿半径、闭合包络和补偿包络。补偿半径标记了所包围的总质量恢复到仅引力作用值的半径，目前在所有三个模型中它通常位于闭合半径之内。闭合包络和补偿包络是晕质量上最大的中值半径。星系群在每十进制的晕质量中对IGM富集的贡献最大，它们携带与晕相关的重子并将重子在最大距离上重新分布。它们设定了闭合包络，在z=0时该包络达到约2-6.5 Mpc，具体取决于模型。在固定晕质量下，闭合半径通常随宇宙时间增加。通过追踪单个晕，我们发现所有晕质量下都存在开放的重子循环，重子被大量重新分布到晕边界之外，而即使是今天最大质量星系团的前身，其重子比例也低于宇宙平均值。补偿包络向低红移方向增长，在z=0时达到约1.5-5.5 Mpc。在整个宇宙时间内，它与物质功率谱恢复到仅引力作用形式的尺度相吻合，从而在重子重新分布的空间范围与反馈对大尺度结构的影响之间建立了直接联系。
英文摘要
Observations of the local Universe show that, except in the most massive galaxy clusters, the baryon fraction within halos falls below the cosmic mean. This deficit can be characterized using the previously established closure radius, the halocentric distance within which the enclosed baryon fraction reaches the cosmic value. Using the TNG, EAGLE and SIMBA simulations, we examine how, when, and on what scales the baryonic and dark matter distributions diverge. At z=0 less than 30% of cosmic baryons reside within galaxy-hosting halos, compared with ~45% of the dark matter, leaving over 70% of all baryons in the IGM. Building on the closure radius, we introduce three further characteristic scales: the compensation radius, closure envelope, and compensation envelope. The compensation radius marks where the enclosed total mass recovers its gravity-only value, and today it typically lies inside the closure radius in all three models. The closure and compensation envelopes are the largest median radii across halo mass. Galaxy groups provide the largest contribution per dex of halo mass to IGM enrichment with halo-associated baryons and redistribute baryons over the largest distances. They set the closure envelope, which reaches ~2-6.5 Mpc at z=0, depending on the model. The closure radius usually increases with cosmic time at fixed halo mass. Tracking individual halos, we find open baryon cycles with substantial redistribution beyond halo boundaries across all halo masses, while even the progenitors of today's most massive clusters fall below the cosmic baryon fraction. The compensation envelope grows toward low redshift, reaching ~1.5-5.5 Mpc at z=0. Across cosmic time, it coincides with the scale on which the matter power spectrum recovers its gravity-only form, establishing a direct link between the spatial extent of baryon redistribution and the impact of feedback on large-scale structure.
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