AI 中文总结
本研究利用Sherwood系列宇宙学流体动力学模拟，量化数值效应与后再电离IGM天体物理信号对三维Lyα森林功率谱的影响，指出数值收敛性对解读高精度Lyα森林测量的重要性。
AI 中文摘要
近期启动及即将开展的光谱巡天项目，如DESI和WST，将提供超过10^6条高红移类星体光谱，实现Lyα森林的密集天区覆盖。这有望让三维Lyα森林功率谱P_{3D,α}成为探测星系际介质（IGM）热历史与电离历史的探针。为利用这一机遇，本研究通过高保真数值模型量化再电离对后再电离时期IGM的印记；采用Sherwood及Sherwood-Relics宇宙学流体动力学模拟，模拟盒大小达160 h⁻¹ cMpc，研究2.4≤z≤4.8范围内，盒大小、质量分辨率及提取网格分辨率对P_{3D,α}的影响。应用Zel'dovich控制变量校正后，模拟体积对多数尺度和方向的影响较小，而降低质量分辨率会产生高达约13%的差异；光深计算所用网格分辨率不足会人为将小尺度功率增强多达约35%。H I再电离的时间在z=2.4时仅对P_{3D,α}留下百分量级的印记，而光加热速率变化2倍会使大尺度功率改变约4-8%。研究结果表明，数值效应可与P_{3D,α}编码的遗迹天体物理信号相当甚至超过，因此数值收敛性对解释高精度Lyα森林测量至关重要；最强的天体物理印记来自空间非均匀H I再电离，其在z=4.2时可将大尺度功率增强多达约70%，凸显后再电离时期Lyα森林测量作为探测宇宙再电离热历史与空间形态的探针的潜力。
英文摘要
Recently initiated and upcoming spectroscopic surveys, such as DESI and WST, will provide more than $10^6$ high-$z$ quasar spectra, enabling dense sky coverage by the Ly$α$ forest. This is expected to establish the three-dimensional (3D) Ly$α$ forest power spectrum, $P_{\rm 3D,α}$, as a probe of the thermal and ionization history of the intergalactic medium (IGM). To exploit this opportunity, we quantify the imprints of reionization on the post-reionization IGM using high-fidelity numerical models. We use the Sherwood and Sherwood-Relics cosmological hydrodynamical simulations with box sizes up to $160\,h^{-1}\,\rm cMpc$ to investigate the impact of box size, mass resolution, and extracted grid resolution on $P_{\rm 3D,α}$ over $2.4\leq z\leq4.8$. After applying a Zel'dovich control variate correction, simulation volume has a modest impact over most scales and orientations, whereas degrading the mass resolution produces differences of up to $\sim13\%$. Insufficient resolution of the grid used for the optical-depth calculation can artificially enhance small-scale power by up to $\sim35\%$. The timing of $\mathrm{H\,I}$ reionization leaves only a percent-level imprint on $P_{\rm 3D,α}$ at $z=2.4$, whereas varying the photoheating rate by a factor of two changes the large-scale power by $\sim4-8\%$. Our results demonstrate that numerical effects can be comparable to, or exceed, the relic astrophysical signatures encoded in $P_{\rm 3D,α}$, making numerical convergence essential for interpreting precise Ly$α$ forest measurements. The strongest astrophysical imprint arises from spatially inhomogeneous $\mathrm{H\,I}$ reionization, which enhances the large-scale power by up to $\sim70\%$ at $z=4.2$. This highlights the potential of post-reionization Ly$α$ forest measurements as a probe of the thermal history and spatial morphology of cosmic reionization.
Comments32+21 pages, 14+7 figures, 1+6 tables, Comments welcome
