Advancing the Search for Isolated Pure Dark Matter Halos

宇宙中大约85%的物质以一种看不见的形式存在，称为暗物质，与原子和其他已知粒子不同。星系是在暗物质密度较高的区域内诞生和生长的，这些区域被称为晕。标准宇宙模型预测，对于每个足够大到可以容纳一个星系的暗物质晕，都会有许多较小的暗物质晕，其中不包含恒星和几乎看不见的气体。这种低质量暗物质晕的丰度和密度分布对暗物质的性质特别敏感。该计划旨在通过对银河系周围亮度最低的星系进行总体研究，来确定星系形成所需的最小暗物质晕质量。即使是更小的暗物质晕，也可以通过引力透镜在宇宙学距离内探测到。研究人员将进行多波长搜索，寻找适合进行详细后续研究的引力透镜。这项工作中使用的天文调查数据集，包括从暗能量调查获得的图像和天体目录，将与数据访问工具、科学验证和文件一起公开发布，以支持研究、教育和外联活动。暗能量调查的科学结果、图像和经验将在几个数字媒体平台上分享，以联系更广泛的受众。该计划包括两个互补的观测、理论和数据分析部分。首先，研究人员将使用一系列光学测量对整个银河系高纬度天空中围绕银河系运行的低亮度星系进行普查。搜索算法结合了精确的多波段光度测量和天体测量，将探测表面亮度极低的星系群。目标是确定暗物质晕质量阈值，低于该阈值的重子对暗物质晕的结构和演化的影响可以忽略不计。其次，研究人员将结合广域光学和射电测量的数据，以扩大高红移、强透镜、射电声活动星系核的样本。多波长搜索预计将产生几个新的目标，用于使用超长基线无线电干涉测量进行高分辨率后续研究。有了这种毫安秒级的角度分辨率观测，就有可能识别出星系形成质量门槛以下的暗物质晕。这一奖项反映了美国国家科学基金会的法定任务，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Approximately 85% of the matter in the Universe exists in an invisible form called dark matter that is distinct from atoms and other known particles. Galaxies are born and grow within regions of higher dark matter density, called halos. The Standard Cosmological Model predicts that for every dark matter halo large enough to host a galaxy, there are many smaller dark matter halos containing no stars and little gas that would be effectively invisible. The abundance and density profiles of such low-mass dark matter halos are especially sensitive to the properties of dark matter. This program aims to determine the minimum dark matter halo mass for galaxy formation by using a population study of the least luminous galaxies around the Milky Way. Even smaller dark matter halos could be detected at cosmological distances via gravitational lensing. The investigator will perform a multiwavelength search for gravitational lenses suitable for detailed follow-up study. Astronomical survey datasets used in this work, including images and object catalogs obtained from the Dark Energy Survey, will be publicly released with data access tools, scientific validation, and documentation to enable research, education, and outreach activities. Science results, images, and experiences from the Dark Energy Survey will be shared on several digital media platforms to connect with broader audiences.The program involves two complementary observational, theoretical, and data analysis components. First, the investigator will conduct a census of low-luminosity galaxies orbiting the Milky Way over the entire high-Galactic-latitude sky using an ensemble of optical surveys. Search algorithms incorporating precise multi-band photometry and astrometry will probe the galaxy population in the extremely low surface brightness regime. The objective is to determine the dark matter halo mass threshold below which baryons have negligible impact on the structure and evolution of dark matter halos. Second, the investigator will combine data from wide-area optical and radio surveys to enlarge the sample of high-redshift strongly lensed radio-loud active galactic nuclei. The multiwavelength search is expected to yield several new targets for high-resolution follow-up with very-long-baseline radio interferometry. With such milliarcsecond- scale angular resolution observations, it would be possible to identify dark matter halos below the mass threshold of galaxy formation.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.