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arXiv 2412.07970astro-ph.GA
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延展红翼与再电离时期莱曼α发射体的可见性

Extended red wings and the visibility of reionization-epoch Lyman-$α$ emitters

Yuxuan Yuan, Sergio Martin-Alvarez, Martin G. Haehnelt, Thibault Garel, Laura Keating, Joris Witstok, Debora Sijacki

AI总结:

本研究通过Azahar模拟发现大质量再电离星系的本征Lyα发射具有显著延展红翼,并合、视角及物理模型均影响其可见性,对推断中性氢比例具有重要意义。

摘要:

再电离时期星系的莱曼α(Lyα)发射可见性,敏感地取决于1215.67 Å红端本征Lyα发射的延展程度。由星际介质中共振辐射转移产生的显著红峰,通常被建模为单个高斯轮廓。我们利用针对一个大质量再电离时期星系的Azahar模拟套件表明,显著更大比例的Lyα发射延展至400–800 km s⁻¹,因此比高斯谱线轮廓所预测的更加显著地向红端延伸。频繁星系并合的循环强烈调节Lyα光度、红峰速度以及从星系显现的延展红翼,而这些量也都随观测视角发生强烈变化。Lyα发射还敏感依赖于所采用的反馈、尘埃和恒星形成物理。如果假设Lyα发射仅受到极少尘埃影响,我们包含宇宙射线的模拟能够很好地再现再电离时期Lyα发射体(LAEs)的观测光谱性质。若不考虑本征Lyα发射的延展红翼,LAEs的可见性可能会被严重低估。我们讨论了利用LAEs可见性约束再电离期间体积平均中性比例演化的意义。

英文摘要:

The visibility of the Lyman-$α$ (Ly$α$) emission from reionization-epoch galaxies depends sensitively on the extent of the intrinsic \lya emission redwards of 1215.67~Å. The prominent red peak resulting from resonant radiative transfer in the interstellar medium is often modelled as a single Gaussian. We use the \textsc{Azahar} simulation suite of a massive-reionization epoch galaxy to show that a significantly larger fraction of the \lya emission extends to $400$-$800$~km~s$^{-1}$, and thus significantly further to the red than predicted by a Gaussian line profile. A cycle of frequent galaxy mergers strongly modulates the \lya luminosity, the red peak velocity and its extended red wing emerging from the galaxy, which all also strongly vary with viewing angle. The \lya emission also depends sensitively on the implemented feedback, dust and star formation physics. Our simulations including cosmic rays reproduce the observed spectral properties of reionization epoch \lya emitters (LAEs) well if we assume that the \lya emission is affected by very little dust. The visibility of LAEs can be strongly underestimated if the extended red wings of the intrinsic \lya emission are not accounted for. We discuss implications for using the visibility of LAEs to constrain the evolution of the volume-averaged neutral fraction during reionization.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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