Collaborative Research: The SAGA Project: Searching for Dwarf Galaxies Around Milky Way Analogs

我们的家乡银河系被几十个较小的星系包围着。这些较小的星系被称为矮星系。这些矮小星系的性质为星系如何形成提供了线索，并可以测试暗物质的性质。然而，银河系矮小星系的数量和它们的性质并不完全符合成熟的宇宙学模型。为了理解这种差异，有必要了解银河系及其矮小星系群是否是典型的大型螺旋星系，或者银河系本身是否是一个不寻常的星系。研究人员将在类似银河系的50个螺旋星系周围识别矮小星系。这些系统将与预测进行比较，以确定银河系的矮星数量是否典型，并将为暗物质的性质和我们银河系的形成提供新的见解。研究人员的工作集中在一个公众感兴趣的关键问题上：我们在宇宙中的位置？他们将把成果融入到他们的一系列教育和外展活动中，将这一快速发展的领域的兴奋带给更广泛的受众。他们将创建一个维基来收集和传播教学资源，目标是降低将新实践引入本科天文学课堂的门槛。尽管创新和互动的本科教材的开发速度加快，但一项针对大学级理科教师的调查显示，其中只有一小部分进入课堂。目前还缺乏一个精心设计的维基百科，可以从教授那里收集创新的本科生天体物理学教学资源，这将大大增加此类材料的使用。研究人员将通过观测识别至少50个系统周围的矮星系群，以限制矮星在银河系质量星系(银河系本身就是一个例子)周围的分布，低至银河系Fornax矮星系的光度(比银河系暗8个数量级)。同时，他们将基于宇宙学暗物质模拟构建一个全面的理论框架，充分利用观测计划的结果，为星系形成和暗物质物理模型提供洞察和新的限制。他们的目标是：(1)提供必要的数据和理论框架，以区分针对“失踪矮星”和“大到不能倒”问题提出的多种解决方案，以及(2)从宇宙学的角度更好地理解银河系本身。

Our home galaxy, the Milky Way, is surrounded by dozens of smaller galaxies. These smaller galaxies are called dwarf galaxies. The properties of these dwarf galaxies provide clues to how galaxies form and can test the nature of dark matter. However, the number of Milky Way dwarf galaxies and their properties do not fully agree with well-established cosmological models. In order to understand this discrepancy, it is necessary to understand whether the Milky Way and its dwarf galaxy populations are typical of large spiral galaxies, or if the Milky Way is itself an unusual galaxy. The investigators will identify dwarf galaxies around 50 spiral galaxies similar to the Milky Way. These systems will be compared to predictions to determine whether the Milky Way's dwarf population is typical, and will provide new insight into the nature of dark matter and into the formation of our own Galaxy.The investigators work focuses on a key question of interest to the public: What is our place in the Universe? They will integrate results into their array of education and outreach activities, bringing the excitement of this rapidly-advancing field to a wider audience. They will create a wiki to collect and disseminate teaching resources, with the goal of lowering the bar to introducing new practices into the undergraduate astronomy classroom. While development of innovative and interactive undergraduate material has accelerated, a survey of university-level science faculty suggests that only a small fraction of this makes it into the classroom. A single well-designed wiki which gathers innovative undergraduate astrophysics teaching resources from the professors who use them is lacking and will significantly increase the use of such material.The investigators will constrain the distribution of dwarfs around Milky Way-mass galaxies (of which the Milky Way itself is a single example) by observationally identifying dwarf galaxy populations around at least 50 systems down to the luminosity of the Milky Way's Fornax dwarf galaxy (eight magnitudes fainter than the Milky Way). In parallel, they will construct a comprehensive theoretical framework based on cosmological dark matter simulations that fully utilizes the results of the observational program to provide insight into and place new constraints on models of galaxy formation and dark matter physics. Their goals are to: (1) provide the data and theoretical framework necessary to distinguish between the multiple proposed solutions to the "missing dwarf" and "too big to fail" problems and (2) provide an improved understanding of the Milky Way itself in a cosmological context.