Extreme Galaxies: The Physical Nature of SMUDGes

星系团是由嵌入在更大的暗物质晕中的正常物质组成的。了解正常物质如何在暗物质晕中分布，对于了解星系如何生长和演化非常重要。该项目将研究超扩散星系（UDG），这是一类大小与银河系相当的星系，但似乎只有很少的恒星。该项目将把以前调查（SMUDG）的联合收割机数据与其他来源的现有数据和新数据结合起来，对UDG的物理特征进行编目。这些特征包括大小、年龄、质量和金属丰度。通过建立一个足够大的目录，该项目将能够更好地了解UDG以及它们在一般星系类别中的位置。该项目还将支持天空大使计划，培训教师在课堂上展示天文学。该项目将在Steward天文台启动一个西班牙语公开讲座系列，并将利用SMUDG巡天中发现的星系建立一个有统计意义的UDG物理性质目录。该项目将使用来自SMUDG的聚类数据来确定密集环境中UDG的距离测量，他们还将使用大型双目望远镜上的光谱观测来获得感兴趣的目标的红移距离，例如那些看起来非常大或处于静止场中的目标。他们将使用存档的紫外线数据来确定UDG的颜色，并且可以标记物理上更有趣的UDG以进行后续光谱分析。由此产生的目录将提供UDG特征的大样本，可用于更好地了解这些对象是否是一个单独的类别，或者它们是否是广泛分布的星系的延伸尾巴。该项目还将继续一项培训小学到高中教师在课堂上使用天文学的计划。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Galaxies consist of normal matter embedded in a larger halo of dark matter. Understanding how normal matter distributes itself within the dark matter halo is important to understanding how galaxies grow and evolve. This project will study ultra-diffuse galaxies (UDGs), a class of galaxies that are comparable in size to the Milky Way, but seem to have very few stars. The project will combine data from a previous survey (SMUDGes) with existing data from other sources and new data to catalog physical characteristics of UDGs. These characteristics include sizes, ages, masses, and metallicities. By building a large enough catalog, this project will be able to better understand UDGs and where they fit into the general class of galaxies. The project will also support the Sky Ambassadors program that trains teachers to present astronomy in their classrooms. It will initiate a Spanish language public lecture series at the Steward Observatory.The project will use galaxies found in the SMUDGes survey to build a statistically meaningful catalog of UDG physical properties. The project will use clustering data from SMUDGes to determine distance measurements to UDGs in dense environments, they will also use spectrographic observations taken on the Large Binocular Telescope to obtain redshift distances for interesting targets such as those that appear to be very large or are in quiescent fields. They will use archival UV data to determine color of UDGs and the more physically interesting ones may be flagged for follow-up spectroscopy. The resulting catalog will provide a large sample of UDG characteristics that can be used to better understand if these objects are a separate class or if they are an extended tail of a broad distribution of galaxies. The project will also continue a program that trains elementary through high-school teachers to use astronomy in their classrooms. They will also initiate and sponsor Spanish language lectures as part of the Steward Observatory Public Lecture Series.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.