Christian Kragh Jespersen, Adam C. Carnall and Christopher C. Lovell
{"title":"Explaining Ultramassive Quiescent Galaxies at 3 < z < 5 in the Context of Their Environments","authors":"Christian Kragh Jespersen, Adam C. Carnall and Christopher C. Lovell","doi":"10.3847/2041-8213/adeb7c","DOIUrl":null,"url":null,"abstract":"The swift assembly of the earliest galaxies poses a significant challenge to our understanding of galaxy formation. Ultramassive quiescent galaxies at intermediate redshifts (3 < z < 5) currently present one of the most pressing problems for theoretical modeling, since very few mechanisms can be invoked to explain how such galaxies formed so early in the history of the Universe. Here, we exploit the fact that these galaxies all reside within significant overdensities to explain their masses. To this end, we construct a modified version of the Extreme Value Statistics (EVS) code, which takes into account galaxy environment by incorporating clustering in the calculation. With this new version of EVS, we find that ultramassive quiescent galaxies at 3 < z < 5 do not present as serious a tension with simple models of galaxy formation when the analysis of a given galaxy is conditioned on its environment.","PeriodicalId":501814,"journal":{"name":"The Astrophysical Journal Letters","volume":"11 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"The Astrophysical Journal Letters","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3847/2041-8213/adeb7c","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
The swift assembly of the earliest galaxies poses a significant challenge to our understanding of galaxy formation. Ultramassive quiescent galaxies at intermediate redshifts (3 < z < 5) currently present one of the most pressing problems for theoretical modeling, since very few mechanisms can be invoked to explain how such galaxies formed so early in the history of the Universe. Here, we exploit the fact that these galaxies all reside within significant overdensities to explain their masses. To this end, we construct a modified version of the Extreme Value Statistics (EVS) code, which takes into account galaxy environment by incorporating clustering in the calculation. With this new version of EVS, we find that ultramassive quiescent galaxies at 3 < z < 5 do not present as serious a tension with simple models of galaxy formation when the analysis of a given galaxy is conditioned on its environment.
最早星系的快速聚集对我们对星系形成的理解提出了重大挑战。处于中间红移(3 < z < 5)的超大质量静止星系目前是理论建模中最紧迫的问题之一,因为很少有机制可以用来解释这样的星系是如何在宇宙历史的早期形成的。在这里,我们利用这些星系都存在于显著的超密度中这一事实来解释它们的质量。为此,我们构建了一个修改版本的极值统计(EVS)代码,该代码通过在计算中加入聚类来考虑星系环境。利用这个新版本的EVS,我们发现,当对给定星系的分析取决于其环境时,3 < z < 5的超大质量静止星系与简单的星系形成模型并不存在严重的张力。