In our modern understanding of galaxy formation, every galaxy forms within a dark matter halo. The formation and growth of galaxies over time is connected to the growth of the halos in which they form. The advent of large galaxy surveys as well as high-resolution cosmological simulations has provided a new window into the statistical relationship between galaxies and halos and its evolution. Here we define this galaxy-halo connection as the multi-variate distribution of galaxy and halo properties that can be derived from observations and simulations. This connection provides a key test of physical galaxy formation models; it also plays an essential role in constraints of cosmological models using galaxy surveys and in elucidating the properties of dark matter using galaxies. We review techniques for inferring the galaxy-halo connection and the insights that have arisen from these approaches. Some things we have learned are that galaxy formation efficiency is a strong function of halo mass; at its peak in halos around a pivot halo mass of 10^12 Msun, less than 20% of the available baryons have turned into stars by the present day; the intrinsic scatter in galaxy stellar mass is small, less than 0.2 dex at a given halo mass above this pivot mass; below this pivot mass galaxy stellar mass is a strong function of halo mass; the majority of stars over cosmic time were formed in a narrow region around this pivot mass. We also highlight key open questions about how galaxies and halos are connected, including understanding the correlations with secondary properties and the connection of these properties to galaxy clustering.

中文翻译：

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星系与其暗物质晕之间的联系

在我们对星系形成的现代理解中，每个星系都在暗物质晕中形成。随着时间的推移，星系的形成和增长与它们形成的光晕的增长有关。大型星系调查以及高分辨率宇宙学模拟的出现为了解星系和晕之间的统计关系及其演化提供了一个新的窗口。在这里，我们将这种星系-晕连接定义为可以从观测和模拟中得出的星系和晕属性的多变量分布。这种连接提供了物理星系形成模型的关键测试；它还在使用星系调查的宇宙学模型的约束和使用星系阐明暗物质的特性方面发挥着重要作用。我们回顾了推断星系-光环连接的技术以及从这些方法中产生的见解。我们了解到，星系形成效率是晕质量的强函数；在围绕 10 ^ 12 Msun 枢轴晕质量的晕达到峰值时，到今天，只有不到 20% 的可用重子变成了恒星；星系恒星质量的内在散射很小，在高于该枢轴质量的给定晕质量下小于 0.2 dex；在这个枢轴质量之下，星系的恒星质量是晕质量的强函数；宇宙时间内的大多数恒星都是在这个枢轴质量周围的狭窄区域中形成的。我们还强调了关于星系和晕如何连接的关键开放性问题，包括理解与次要属性的相关性以及这些属性与星系团的联系。