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arXiv 2511.19600astro-ph.COastro-ph.GA
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迈向弥合再电离与JWST:亮星系与强反馈的作用

Towards Reconciling Reionization with JWST: The Role of Bright Galaxies and Strong Feedback

University of Maryland, College Park(马里兰大学帕克分校);Space Telescope Science Institute(太空望远镜科学研究所);University of Zurich(苏黎世大学);University of Edinburgh(爱丁堡大学);University of the Western Cape(西开普大学);New Mexico State University(新墨西哥州立大学);University of Copenhagen(哥本哈根大学);Technical University of Denmark(丹麦技术大学)

Ankita Bera, Sultan Hassan, Robert Feldmann, Romeel Davé, Kristian Finlator

AI总结:

研究通过半解析框架联合校准JWST观测与再电离观测,发现强反馈和亮星系贡献能匹配JWST UVLF,但高估亮端;弱反馈模型则无法匹配高红移UVLF,但再电离历史更渐进,与CMB约束一致。

摘要:

近期詹姆斯·韦伯太空望远镜(JWST)观测到的紫外光子亮度函数(UVLF)挑战了现有理论模型的可行性。为此,我们采用半解析框架,结合基于辐射传输流体动力学模拟的物理源模型和马尔可夫链蒙特卡洛采样器,对JWST星系观测(UVLF、ϕ_{UV}和紫外亮度密度ρ_{UV})和再电离时期观测(电离发射率\dot{N}_{ion}、中性氢分数x_{HI}和汤姆逊光学深度τ)进行联合校准。我们发现,具有弱反馈和更多来自暗弱星系贡献的模型能再现再电离观测,但难以匹配高红移JWST UVLF。相反,具有强反馈(即快速红移演化)和更多来自亮星系贡献的模型能再现JWST UVLF,但高估亮端。受JWST UVLF约束的强反馈模型预测再电离历史更渐进且延长,与弱反馈模型的突然再电离不同。这种延长的再电离(z≈16-6)产生与宇宙微波背景(CMB)约束一致的光学深度(2-σ),从而缓解了光子预算危机。在两种情况下,再电离在z≈6时完成,与当前数据一致。我们的分析强调了准确建模大爆炸后一亿年内的反馈和不同源群体的电离发射率的重要性。

英文摘要:

The elevated UV luminosity functions (UVLF) from recent James Webb Space Telescope (JWST) have challenged the viability of existing theoretical models. To address this, we use a semi-analytical framework -- which couples a physically motivated source model derived from radiative-transfer hydrodynamic simulations of reionization with a Markov Chain Monte Carlo sampler -- to perform a joint calibration to JWST galaxy surveys (UVLF, $ϕ_{\rm UV}$ and UV luminosity density, $ρ_{\rm UV}$) and reionization-era observables (ionizing emissivity, $\dot{N}_{\rm ion}$, neutral hydrogen fraction, $x_{\rm HI}$, and Thomson optical depth, $τ$). We find that models with weak feedback and a higher contribution from faint galaxies reproduce the reionization observables but struggle to match the elevated JWST UVLF at $z > 9$. In contrast, models with stronger feedback (i.e., rapid redshift evolution) and a higher contribution from bright galaxies successfully reproduce JWST UVLF at $z \geq 10$, but over-estimate the bright end at $z < 9$. The strong-feedback model constrained by JWST UVLF predicts a more gradual and extended reionization history, as opposed to the sudden reionization seen in the weak-feedback models. This extended nature of reionization ($z\sim 16$ - $6$) yields an optical depth consistent (at 2-$σ$) with the Cosmic Microwave Background (CMB) constraint, thereby alleviating the photon-budget crisis. In both scenarios, reionization is complete by $z \sim 6$, consistent with current data. Our analysis highlights the importance of accurately modeling feedback and ionizing emissivities from different source populations during the first billion years after the Big Bang.

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