论文标题
使用半数字光子支持代码脚本来限制宇宙的电离和热历史
Constraining the reionization and thermal history of the Universe using a semi-numerical photon-conserving code SCRIPT
论文作者
论文摘要
鉴于宇宙氢的电离历史尚未受到严格的限制，因此值得检查这样做的前景，并使用出色动机的模型和可用的观察数据。为此，我们使用了明确的光子连接半数字电离模型的扩展版本，$ \ texttt {script} $，其中还包括Intergalactic培养基（IGM）的热演化。该模型结合了不均匀的重组和辐射反馈的效果，自兼容，具有五个自由参数（两个用于红移依赖性电离效率的参数，两个用于电离逃逸分数，另一个用于恢复温度的增量）。我们通过与各种观察探针（例如电离氢分数，CMB散射光学深度和星系紫外线光度函数）同时匹配来限制这些自由参数。此外，我们还包括从$ z \ sim 5.5 $的Lyman-$α$吸收光谱获得的低密度IgM温度测量值，这是贝叶斯对贝叶斯的探测，用于贝叶斯对避孕参数的分析。我们发现，各种数据集的相互作用，尤其是温度数据的包含，导致参数约束的收紧。我们的默认模型更喜欢与其他研究一致的电源末端（$ z \ Lessim 6 $）。我们还可以根据电离持续时间获得限制，$Δz= 1.81^{+0.51} _ { - 0.67} $和电源中点，$ z _ {\ sathrm {methrm {midrm {midrm {mid}} = 7.0^{+0.30} {+0.30} _ { - 0.40} $。通过包括其他可用的和即将到来的数据集，可以进一步收紧约束。
Given that the reionization history of cosmic hydrogen is yet to be stringently constrained, it is worth checking the prospects of doing so using physically motivated models and available observational data. For this purpose, we use an extended version of the explicitly photon-conserving semi-numerical model of reionization, $\texttt{SCRIPT}$, which also includes thermal evolution of the intergalactic medium (IGM). The model incorporates the effects of inhomogeneous recombination and radiative feedback self-consistently and is characterized by five free parameters (two for the redshift-dependent ionization efficiency, two for the ionizing escape fraction, and another for reionization temperature increment). We constrain these free parameters by simultaneously matching with various observational probes, e.g., estimates of the ionized hydrogen fraction, the CMB scattering optical depth and the galaxy UV luminosity function. In addition, we include the low-density IGM temperature measurements obtained from Lyman-$α$ absorption spectra at $z \sim 5.5$, a probe not commonly used for Bayesian analysis of reionization parameters. We find that the interplay of the various data sets, particularly inclusion of the temperature data, leads to tightening of the parameter constraints. Our default models prefer a late end of reionization (at $z \lesssim 6$), in agreement with other recent studies. We can also derive constraints on the duration of reionization, $Δz=1.81^{+0.51}_{-0.67}$ and the midpoint of reionization, $z_{\mathrm{mid}}=7.0^{+0.30}_{-0.40}$. The constraints can be further tightened by including other available and upcoming data sets.
