高红移紫外光度函数中爆发式恒星形成的双重特征
Dual Signatures of Bursty Star Formation in High-Redshift UV Luminosity Functions
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中文总结 AI 辅助
本研究利用丰度匹配方法，揭示高红移紫外光度函数中暗端陡峭斜率与亮端丰度是低质量晕中爆发式恒星形成的双重特征，紫外变率可统一解释$z\simeq7$的SFE与$z\gtrsim12$的亮星系丰度，并为JWST和Roman提供诊断。
中文摘要 AI 辅助
紫外光度函数（UVLF）编码了关于星系形成的关键信息。在$z\gtrsim10$处缓慢演化的亮端UVLF使得爆发式恒星形成引起的紫外变率成为一个有前景的解释，但这种变率的影响不必局限于亮端。受$z\simeq7$处UVLF的超深测量的启发，我们研究了紫外变率能否为$z\simeq7$处的低质量恒星形成效率（SFE）和$z\gtrsim12$处紫外亮星系的丰度提供统一的解释。利用丰度匹配，我们表明$z\simeq7$处陡峭的暗端UVLF允许一系列解释。对于适度的、与质量无关的紫外变率，推断的中值SFE在$M_{\rm h} \sim10^{10.5} M_{\odot}$以下开始变平。如果紫外变率反而随着暗物质晕质量的减小而增大——这一可能性由模拟和观测所激发——那么推断的中值SFE在$\sim10^9 M_{\odot}$处更陡峭且低约三倍，这与低质量晕中更强的反馈抑制一致。以共同的$z\simeq7$ UVLF目标为校准，在红移无关的紫外变率和SFE假设下，这两种情景外推到$12\lesssim z\lesssim17$时产生强烈分歧。强质量依赖的$M_\mathrm{UV}$散射将$z\simeq7$处陡峭的暗端斜率与$z\gtrsim12$处高亮端丰度联系起来，作为类似低质量晕中爆发性的双重特征。更强的变率使亮星系贡献更大比例的紫外光度密度，而较弱的变率则有利于暗弱源，尽管它们预测的再电离历史相似。在固定的$M_\mathrm{UV}$下，紫外变率拓宽了晕质量分布并降低了成团偏置，这为JWST和Roman提供了有用的爆发性诊断。
英文摘要
The UV luminosity function (UVLF) encodes key information about galaxy formation. The slowly evolving bright-end UVLFs at $z\gtrsim10$ have made UV variability from bursty star formation a promising explanation, but the impact of such variability need not be restricted to the bright end. Motivated by ultra-deep measurements of the $z\simeq7$ UVLF, we investigate whether UV variability can provide a unified interpretation of the low-mass star formation efficiency (SFE) at $z\simeq7$ and the abundance of UV-bright galaxies at $z\gtrsim12$. Using abundance matching, we show that a steep faint-end UVLF at $z\simeq7$ admits a range of interpretations. For modest, mass-independent UV variability, the inferred median SFE starts flattening below $M_{\rm h} \sim10^{10.5} M_{\odot}$. If UV variability instead grows with decreasing halo mass---a possibility motivated by simulations and observations---the inferred median SFE is steeper and lower by a factor of about three at $\sim10^9 M_{\odot}$, consistent with stronger feedback suppression in low-mass halos. Calibrated to the common target $z\simeq7$ UVLF, these two scenarios diverge strongly when extrapolated to $12\lesssim z\lesssim17$ under redshift-independent UV variability and SFE prescriptions. Strongly mass-dependent $M_\mathrm{UV}$ scatter links the steep $z\simeq7$ faint-end slope and high $z\gtrsim12$ bright-end abundance as dual signatures of burstiness in similarly low-mass halos. Stronger variability makes bright galaxies contribute a larger fraction of the UV luminosity density, whereas weaker variability favors faint sources, despite their similar predicted reionization histories. At fixed $M_\mathrm{UV}$, UV variability broadens the halo mass distribution and lowers the clustering bias, which provides a useful diagnostic of burstiness for JWST and Roman.
发表机构
- Northwestern University（西北大学）
- University of California, Los Angeles（加州大学洛杉矶分校）
- University of Pennsylvania（宾夕法尼亚大学）
机构由 AI 辅助整理，请以论文原文为准。
