Andromeda’s asymmetric satellite system as a challenge to cold dark matter cosmology

IF 14.3 1区物理与天体物理 Q1 ASTRONOMY & ASTROPHYSICS

Nature Astronomy Pub Date : 2025-04-11 DOI:10.1038/s41550-025-02480-3

Kosuke Jamie Kanehisa, Marcel S. Pawlowski, Noam Libeskind

引用次数: 0

Abstract

The Andromeda galaxy is surrounded by a strikingly asymmetrical distribution of satellite dwarf galaxies aligned towards the Milky Way. The standard model of cosmology predicts that most satellite galaxy systems are near-isotropic, and dwarf associations observed in the local Universe are only weakly asymmetric. Here we characterize the Andromeda system’s asymmetry and test its agreement with expectations from concordance cosmology. All but one of Andromeda’s 37 satellite galaxies are contained within 107° of our Galaxy. In standard cosmological simulations, less than 0.3% (0.5% when accounting for possible observational incompleteness) of Andromeda-like systems show a comparably significant asymmetry. None are as collectively lopsided as the observed satellite configuration. In conjunction with its satellite plane, our results paint the Andromeda system as an extreme outlier in the prevailing cosmological paradigm, further challenging our understanding of structure formation at small scales.

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仙女座星系的不对称卫星系统是对冷暗物质宇宙学的挑战

仙女座星系被一群分布极不对称的卫星矮星系包围着，这些卫星矮星系朝向银河系排列。宇宙学的标准模型预测，大多数卫星星系系统是接近各向同性的，而在局部宇宙中观测到的矮星系只是弱不对称的。在这里，我们描述了仙女座星系的不对称性，并测试了它与协和宇宙学的期望的一致性。仙女座的37个卫星星系中，除了一个外，其余都位于我们银河系的107°范围内。在标准的宇宙学模拟中，不到0.3%（考虑到可能的观测不完整性时为0.5%）的仙女座类系统显示出相当显著的不对称性。没有一个像观测到的卫星结构那样整体不平衡。结合其卫星平面，我们的研究结果将仙女座星系描绘成主流宇宙学范式中的一个极端异常，进一步挑战了我们对小尺度结构形成的理解。

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

期刊介绍： Nature Astronomy, the oldest science, has played a significant role in the history of Nature. Throughout the years, pioneering discoveries such as the first quasar, exoplanet, and understanding of spiral nebulae have been reported in the journal. With the introduction of Nature Astronomy, the field now receives expanded coverage, welcoming research in astronomy, astrophysics, and planetary science. The primary objective is to encourage closer collaboration among researchers in these related areas. Similar to other journals under the Nature brand, Nature Astronomy boasts a devoted team of professional editors, ensuring fairness and rigorous peer-review processes. The journal maintains high standards in copy-editing and production, ensuring timely publication and editorial independence. In addition to original research, Nature Astronomy publishes a wide range of content, including Comments, Reviews, News and Views, Features, and Correspondence. This diverse collection covers various disciplines within astronomy and includes contributions from a diverse range of voices.