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面向早期宇宙的星系自旋重定向记忆

Reoriented Memory of Galaxy Spins for the Early Universe

Jun-Sung Moon, Jounghun Lee

备注：
Accepted for publication in ApJ, revised version, improved analysis and more details about analytic modeling
发表信息：
Astrophys. J. 952 (2023) 101
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AI总结：

本文利用高分辨率流体动力学模拟追溯星系粒子，发现当前恒星自旋虽保留早期宇宙记忆，却由与初始潮汐场中间轴对齐转为与主轴相关，并提出单参数解析模型描述该重定向。

摘要：

星系自旋被认为保留了最初获得的、与线性潮汐场中间主轴对齐的倾向，这为将其用作早期宇宙物理学探针带来了前景。然而，这一美好前景取决于一个关键假设：在内部半径处测量的当前星系可观测恒星自旋，与在维里边界处测量的其暗物质对应物一样，对初始潮汐场具有相同的对齐倾向。我们通过将星系组成粒子追溯至原星系阶段，在高分辨率流体动力学模拟中直接检验了这一假设。研究发现，z=0 时的星系恒星自旋对早期宇宙具有强烈但经过重定向的记忆，并表现出与 z=127 时初始潮汐场的主要主轴显著互相关的信号。本文构建了一个用于描述当前星系恒星自旋相对于初始潮汐场这种重定向的解析单参数模型，并证明该模型与数值结果高度吻合。

英文摘要：

Galaxy spins are believed to retain the initially acquired tendency of being aligned with the intermediate principal axes of the linear tidal field, which disseminates a prospect of using them as a probe of early universe physics. This roseate prospect, however, is contingent upon the key assumption that the observable stellar spins of the present galaxies measured at inner radii have the same alignment tendency toward the initial tidal field as their dark matter counterparts measured at virial limits. We test this assumption directly against a high-resolution hydrodynamical simulation by tracing back the galaxy component particles back to the protogalactic stage. It is discovered that the galaxy stellar spins at $z=0$ have strong but {\it reoriented} memory for the early universe, exhibiting a significant signal of cross-correlation with the {\it major} principal axes of the initial tidal field at $z=127$. An analytic single-parameter model for this reorientation of the present galaxy stellar spins relative to the initial tidal field is devised and shown to be in good accord with the numerical results.

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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