Surprisingly faint first galaxies

IF 12.9 1区物理与天体物理 Q1 ASTRONOMY & ASTROPHYSICS

Nature Astronomy Pub Date : 2025-05-21 DOI:10.1038/s41550-025-02569-9

Lindsay Oldham

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Abstract

A puzzling feature of cosmic dawn is that bright galaxies in the redshift range 10 < z < 15 are overabundant relative to HST-based expectations but have so far evaded detection at higher redshifts, despite JWST’s technical capacity to do so. Vasily Kokorev and colleagues take advantage of the lensing magnification of the galaxy cluster Abell S1063 and the ultra-deep NIRCam survey GLIMPSE to identify two robust candidates at z > 16.

Combining a Lyman-alpha dropout search with photometric redshift estimates to rule out star-bursting interlopers, the authors narrow down an initial catalogue of lensed background sources to these two final objects, with putative redshifts in the range z ~ 15.8−16.4. Though their ~200 pc effective radii and low dust content are consistent with expectations for very newly formed galaxies, photometric modelling indicates low star formation rate surface densities relative to extrapolations from lower redshifts. Equally surprising is that the volume searched behind the cluster implies a significantly higher number density than expected based on upper limits from previous JWST surveys, in which no strong candidates have yet been found at these redshifts.

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令人惊讶的微弱第一星系

宇宙黎明的一个令人困惑的特征是，红移范围10 <；z & lt;相对于基于hst的预期，其中15个数量过多，但迄今为止，尽管JWST的技术能力可以做到这一点，但它们在更高的红移下仍未被检测到。Vasily Kokorev和他的同事利用Abell S1063星系团的透镜放大和超深NIRCam调查GLIMPSE来确定z >；16.结合Lyman-alpha dropout搜索和光度红移估计来排除恒星爆发闯入者，作者将透镜背景源的初始目录缩小到这两个最终对象，假定红移范围在z ~ 15.8−16.4。虽然它们约200pc的有效半径和低尘埃含量与新形成星系的预期一致，但光度模型表明，相对于较低红移的外推，恒星形成率表面密度较低。同样令人惊讶的是，在星团后面搜索的体积表明，基于之前JWST调查的上限，在这些红移中还没有发现强有力的候选者，这意味着明显更高的数字密度。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Nature Astronomy Physics and Astronomy-Astronomy and Astrophysics

CiteScore

19.50

自引率

2.80%

发文量

252

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