无路可逃：再电离观测不支持过大的再电离光深值
No way ou$τ$: Epoch of Reionization Observations Do not Support Large Values of the Optical Depth to Reionization
AI总结：
该研究结合CMB、BAO及再电离相关观测数据，采用Gompertzian再电离框架分析，得出再电离光深为0.067±0.011，在大于约2σ水平上偏好动力学暗能量，大尺度极化的系统误差难以解释该偏好。
AI中文摘要：
近期结合高红移宇宙微波背景（CMB）测量与低红移重子声学振荡（BAO）数据的宇宙学分析，报告了对动力学暗能量的偏好，其中宇宙学常数模型（ΛCDM）被排斥在约3σ水平。然而，这些分析通常依赖大尺度CMB极化测量来约束再电离光深τ_reio≈0.06，这引发了一个问题：该数据集的潜在系统误差是否会影响推断出的宇宙学偏好。排除大尺度极化数据后，与ΛCDM的张力显著减弱至小于2σ水平，但代价是τ_reio大幅增加至约0.09。在此，我们使用具有物理动机的Gompertzian再电离框架，进行自洽贝叶斯分析，结合CMB（排除大尺度极化数据）、BAO以及类星体阻尼翼观测和暗像素约束给出的中性氢丰度演化的独立测量。我们推导出τ_reio=0.067±0.011，与包含大尺度CMB极化数据的宇宙学分析结果吻合良好，且推断出的再电离历史与多个观测约束一致。我们的分析在大于约2σ水平上恢复了对动力学暗能量的偏好。这些结果表明，再电离的天体物理探针独立地恢复了CMB极化测量所需的光深，提示仅大尺度极化中的潜在系统误差不太可能完全解释新兴的对动力学暗能量的偏好。
英文摘要：
Recent cosmological analyses combining high-redshift cosmic microwave background (CMB) measurements with low-redshift baryon acoustic oscillation (BAO) data have reported a preference for dynamical dark energy, with the cosmological constant scenario ($Λ$CDM) disfavored at the $\sim 3σ$ level. These analyses, however, typically rely on large-scale CMB polarization measurements to constrain the optical depth to reionization $τ_{\rm reio}\sim 0.06$, raising the question of whether potential systematics in this dataset could influence the inferred cosmological preference. Excluding large-scale polarization data substantially weakens the tension with $Λ$CDM to the $\lesssim 2σ$ level, nevertheless at a price of increasing $τ_{\rm reio}$ significantly to $\sim 0.09$. Here, we use a physically motivated Gompertzian reionization framework to perform a self-consistent Bayesian analysis combining CMB (excluding large-scale polarization data), BAO, and independent measurements of the neutral hydrogen fraction evolution from quasar damping wing observations and dark pixel constraints. We derive $τ_{\rm reio} = 0.067 \pm 0.011$ (dynamical dark energy scenario) in good agreement with cosmological analyses that would include large-scale CMB polarization data, while the inferred reionization history is consistent with multiple observational constraints. Our analysis recovers a preference for dynamical dark energy at the $\gtrapprox2σ$ level. These results demonstrate that astrophysical probes of reionization independently recover the optical depth required by CMB polarization measurements, suggesting that potential systematics in large-scale polarization alone are unlikely to fully explain the emerging preference for dynamical dark energy.
