A population of ultraviolet-dim protoclusters detected in absorption
A population of ultraviolet-dim protoclusters detected in absorption
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DOI：
10.1038/s41586-022-04681-6
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发表时间：
2022-06
期刊：
影响因子：
64.8
通讯作者：
A. Newman;G. Rudie;G. Blanc;Mahdi Qezlou;Simeon Bird;D. Kelson;V. P'erez;E. Congiu;B. Lemaux;A. Dressler;J. Mulchaey
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作者：
A. Newman;G. Rudie;G. Blanc;Mahdi Qezlou;Simeon Bird;D. Kelson;V. P'erez;E. Congiu;B. Lemaux;A. Dressler;J. Mulchaey
星系原星系团最终将成长为我们在本地宇宙中看到的大质量星系团，通常通过定位星系的超密度来追踪。现在已经有了对遥远星系的大型光谱观测，但它们的灵敏度主要取决于星系的恒星形成活动和尘埃含量，而不是它的质量。因此，需要不依赖于星系成分的大质量原星团的示踪剂。在这里，我们报告的莱曼-α吸收的背景星系的密集网格的光谱观测，我们使用它来定位大量的候选原星系团的红移2.2至2.8通过他们的星系际气体。我们发现，产生最大吸收的结构，其中大部分是以前未知的，包含令人惊讶的是很少的星系相比，它们的类似物在宇宙学模拟的暗物质含量。几乎所有的结构都被认为是原星系团，我们推断，它们预期的星系成员中有一半在我们的调查中失踪，因为它们在静止帧紫外线波长下异常暗淡。我们把这归因于原星系团环境对这些星系演化的意外强烈和早期影响，这些影响减少了它们的星星形成或增加了它们的尘埃含量。
Galaxy protoclusters, which will eventually grow into the massive clusters we see in the local Universe, are usually traced by locating overdensities of galaxies. Large spectroscopic surveys of distant galaxies now exist, but their sensitivity depends mainly on a galaxy’s star-formation activity and dust content rather than its mass. Tracers of massive protoclusters that do not rely on their galaxy constituents are therefore needed. Here we report observations of Lyman-α absorption in the spectra of a dense grid of background galaxies,, which we use to locate a substantial number of candidate protoclusters at redshifts 2.2 to 2.8 through their intergalactic gas. We find that the structures producing the most absorption, most of which were previously unknown, contain surprisingly few galaxies compared with the dark-matter content of their analogues in cosmological simulations,. Nearly all of the structures are expected to be protoclusters, and we infer that half of their expected galaxy members are missing from our survey because they are unusually dim at rest-frame ultraviolet wavelengths. We attribute this to an unexpectedly strong and early influence of the protocluster environment,on the evolution of these galaxies that reduced their star formation or increased their dust content.