The origin and evolution of galaxies

我建议研究银河系结构在宇宙时间内的演化。这项研究将在大约110亿年的时间范围内探测星系，这一时间范围涵盖了宇宙中主要的恒星质量积累阶段。这项拟议的研究的核心问题是：星系在高红移时是什么样子的？我们怎样才能最好地量化地描述这些系统呢？哈勃序列是如何从这些遥远的星系中出现的？星系结构的变化如何映射到星系演化的基本物理概念上？这项拟议的研究是对局部群中非常近的星系的调查(重点是已分解的恒星群)，以及对已知存在的红移最高的星系的调查的补充。 这项拟议中的研究的一个中心主题是调查“红块”，这是一个非常紧密的大质量演化星系的惊人数量，在遥远的宇宙中，似乎大约是最近宇宙中的三倍。这些天体是我的团队几年前发现的，我的研究试图更好地理解这些星系变大的机制。了解这些星系性质的一种方法是获得它们的详细光谱，这可以探索它们的年龄、恒星形成历史和化学成分。另一种方法是在一般星系群的背景下研究它们，由于机器视觉的最新进展，现在可以比过去更详细地描述星系群的结构。其他领域的技术进步也在推动这一领域向前发展。特别是，我将描述如何使用附近星系中非常微弱的结构的成像来测试星系形成模型的中心预测。

I propose to investigate the evolution of galactic structures over cosmic time. This research will probe galaxies over a time range of about 11 billion years, which encompasses the major stellar mass-building phase of the universe. The central questions underlying the proposed research are: What did galaxies look like at high redshifts? How can we best describe these systems in a quantitative way? How does the Hubble Sequence emerge from these distant galaxies? How do changes in galactic structure map onto ideas for the underlying physics of galaxy evolution? The proposed research is complementary to investigations of very nearby galaxies in the Local Group (which focus on resolved stellar populations), and to investigations of galaxies at the highest redshifts at which they are known to exist. A central theme of the proposed research is the investigation of "red nuggets", an astonishing population of very compact massive evolved galaxies that appear to be about a factor of three smaller in the distant Universe than their closest nearby counterparts. These objects were discovered by my team several years ago, and my research seeks to better understand the mechanisms by which such galaxies grow in size. One way to understand the nature of these galaxies is to obtain detailed spectroscopy of them, which probes their ages, star-formation history and chemical composition. Another approach is to study them in the context of the general galaxy population, whose structure can now be described in far more detail than has been possible in the past, because of recent advances in machine vision. Technological advances in other areas are also driving this field forward. In particular, I will describe a how imaging of very faint structures in nearby galaxies can be used to test central predictions of galaxy formation models.