发表机构
Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences; School of Astronomy and Space Science, University of Science and Technology of China; National Astronomical Observatories, Chinese Academy of Sciences; School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院紫金山天文台暗物质与空间天文重点实验室; 中国科学技术大学天文与空间科学学院; 中国科学院国家天文台; 中国科学院大学天文与空间科学学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过高分辨率宇宙学模拟，发现原初磁场加速早期星系形成，但其特征随红移降低而减弱，且影响取决于功率谱峰值尺度，强调重子反馈在量化其效应中的关键作用。
AI 中文摘要
原初磁场（PMFs）可能在宇宙暴胀或早期宇宙相变期间产生，通过增强再复合后的物质功率谱来改变宇宙结构的形成。在本工作中，我们利用一系列高分辨率宇宙学流体动力学模拟，演化至$z=0$，研究了原初磁场对星系形成的影响。我们的模拟以原初磁场诱导的物质功率谱增强为初始条件，并包含了比以往工作更全面的重子子网格模型，同时纳入了恒星反馈和活动星系核（AGN）反馈。我们发现，原初磁场系统地加速了早期结构形成，产生了更丰富的暗物质晕和星系，更高的重子分数，增强的恒星形成率，以及在高红移（$z \sim 10$）时超大质量黑洞的快速生长。然而，由此增强的恒星和活动星系核反馈有效地处理和排出气体，减少了原初磁场与标准$\Lambda$CDM模型之间的晚期差异。因此，原初磁场的特征在高红移时最强，并随着非线性演化和重子反馈主导初始原初磁场诱导增强而逐渐向低红移减弱。原初磁场的影响强烈依赖于初始功率增强的特征峰值尺度$k_{\rm peak}$，具有相似$k_{\rm peak}$的模型即使其他原初磁场参数不同，也会产生相似的非线性演化。我们的结果强调了全面的重子物理在准确量化原初磁场特征中的关键作用。
英文摘要
Primordial magnetic fields (PMFs), potentially generated during cosmic inflation or early-universe phase transitions, can modify cosmic structure formation by enhancing the post-recombination matter power spectrum. In this work, we investigate the impact of PMFs on galaxy formation using a suite of high-resolution cosmological hydrodynamical simulations evolved to $z=0$. Our simulations are initialized with PMF-induced enhancements to the matter power spectrum and include more comprehensive baryonic subgrid models than previous work, incorporating both stellar and AGN feedback. We find that PMFs systematically accelerate early structure formation, producing more abundant halos and galaxies, higher baryon fractions, enhanced star formation rates, and rapid growth of supermassive black holes at high redshifts ($z \sim 10$). However, the resulting enhanced stellar and AGN feedback efficiently processes and expels gas, reducing the late-time differences between PMF and standard $Λ$CDM models. The PMF signatures are therefore strongest at high redshift and gradually weaken toward low redshift as nonlinear evolution and baryonic feedback dominate over the initial PMF-induced enhancements. The impact of PMFs depends strongly on the characteristic peak scale, $k_{\rm peak}$, of the initial power enhancement, with models yielding similar non-linear evolution if they share a similar $k_{\rm peak}$, even when other PMF parameters differ. Our results highlight the critical role of comprehensive baryonic physics in accurately quantifying PMF signatures.
Comments23pages, 12figures, Accepted for publication in Physical Review D
