Title: Rapid and Late Cosmic Reionization Driven by Massive Galaxies: a Joint Analysis of Constraints from 21-cm, Lyman Line & CMB Data Sets Show Chinese title

Title: 快速和晚期宇宙再电离由大质量星系驱动：21厘米、莱曼线和CMB数据集的联合分析

Abstract: Observations of the Epoch of Reionization (EoR) have the potential to answer long-standing questions of astrophysical interest regarding the nature of the first luminous sources and their effects on the intergalactic medium (IGM). We present astrophysical constraints from a Neural Density Estimation-Accelerated Bayesian joint analysis of constraints deriving from Cosmic Microwave Background power spectrum measurements from Planck and SPT, IGM neutral fraction measurements from Lyman-line-based data sets and 21-cm power spectrum upper limits from HERA, LOFAR and the MWA. In the context of the model employed, the data is found to be consistent with galaxies forming from predominantly atomic-cooled hydrogen gas in dark matter halos, with masses $M_\mathrm{min} \gtrsim 2.6 \times 10^{9}~M_{\odot} ((1+z)/10)^{\frac{1}{2}}$ at 95% credibility ($V_\mathrm{c} \gtrsim 50~\mathrm{km~s^{-1}}$) being the dominant galactic population driving reionization. These galaxies reionize the neutral hydrogen in the IGM over a narrow redshift interval ($\Delta z_\mathrm{re} < 1.8$ at 95% credibility), with the midpoint of reionization (when the sky-averaged IGM neutral fraction is 50%) constrained to $z_{50} = 7.16^{+0.15}_{-0.12}$. Given the parameter posteriors from our joint analysis, we find that the posterior predictive distribution of the global 21-cm signal is reduced in amplitude and shifted to lower redshifts relative to the model prior. We caution, however, that our inferences are model-dependent. Future work incorporating updated, mass-dependent star formation efficiencies in atomic cooling halos, informed by the latest UV luminosity function constraints from the James Webb Space Telescope, promises to refine these inferences further and enhance our understanding of cosmic reionization. Show Chinese abstract

Abstract: 观测再电离时代（EoR）的潜力可以回答天体物理领域长期存在的问题，关于第一个发光源的性质及其对星系际介质（IGM）的影响。 我们从神经密度估计加速的贝叶斯联合分析中得出天体物理约束，这些约束来自普朗克和SPT的宇宙微波背景功率谱测量、基于莱曼线的数据集的IGM中性分数测量以及HERA、LOFAR和MWA的21厘米功率谱上限。 在所采用的模型背景下，数据被发现与主要由原子冷却氢气形成的星系一致，质量为$M_\mathrm{min} \gtrsim 2.6 \times 10^{9}~M_{\odot} ((1+z)/10)^{\frac{1}{2}}$的星系（在95%可信度下，$V_\mathrm{c} \gtrsim 50~\mathrm{km~s^{-1}}$）是驱动再电离的主要星系群体。 这些星系在狭窄的红移区间内再电离IGM中的中性氢（在95%可信度下，$\Delta z_\mathrm{re} < 1.8$），再电离的中点（当天空平均IGM中性分数为50%时）被限制为$z_{50} = 7.16^{+0.15}_{-0.12}$。 鉴于我们联合分析的参数后验分布，我们发现全局21厘米信号的后验预测分布的幅度减小，并相对于模型先验向较低红移移动。 然而，我们提醒，我们的推论是依赖于模型的。 未来的工作将结合更新的、质量相关的原子冷却晕中的恒星形成效率，这些效率由詹姆斯·韦布空间望远镜最新的紫外光度函数约束提供，有望进一步细化这些推论并增强我们对宇宙再电离的理解。