Collaborative Research: The Physical Halo Model

暗物质在自身引力作用下聚集，形成紧密结合的团块，称为暗物质“晕”。当这些光晕形成时，它们将普通物质的原子拉入其中，使我们今天看到的恒星和星系得以形成。因此，暗物质晕是我们理解星系如何在宇宙中分布的基本基石。在过去的几年里，各种研究表明，我们对暗物质晕的定义没有充分地捕捉到它们的内部结构，这损害了我们在解释天文观测数据时使用基于晕的宇宙描述的能力。亚利桑那大学和马里兰大学的科学家合作提出，通过提供第一个完全由物理驱动的暗物质晕定义来解决这一不足。在此基础上，该团队将开发一个准确的理论模型来解释大型星系调查的数据。亚利桑那大学首席研究员将积极参与图森少数民族参与STEM计划，组织研讨会，并协调该计划的指导活动。马里兰大学的首席研究员将为代码巨人开发一个用户友好的网络界面，以实现简单的可视化，可用于入门和非主要天文学课程。这个项目建议对暗物质晕进行彻底的重新定义，从而能够建立大尺度结构的百分比级准确的晕模型。该模型建立在围绕光晕运行的粒子和首次落入光晕的粒子之间的固有二分法之上。提议小组已经证明，轨道和流入对晕关联函数的贡献大致对应于传统晕模型的单晕项和双晕项。然而，与传统的光晕模型方法相比，轨道/流入光晕模型框架在数学上更简单，而且精度更高。该团队将开发基于轨道/流入二分法的拟议物理晕模型框架。然后，他们将根据修改后的晕定义为广泛的模拟宇宙学和红移构建晕星表，并使用产生的晕星表来校准晕质量函数、偏差函数和各种晕关联函数。这项工作产生的代码和光环目录将公开提供。这一奖项反映了NSF的法定使命，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。

Dark matter aggregates under its own gravity to form tightly bound clumps called dark matter “halos”. As these halos form, they pull atoms of regular matter into them, enabling the formation of the stars and galaxies we see today. For this reason, dark matter halos are the foundational building blocks for our understanding of how galaxies are distributed in the Universe. Over the past few years, a variety of works have demonstrated that our definitions of dark matter halos do not adequately capture their inner structure, compromising our ability to use a halo-based description of the Universe when interpreting astronomical survey data. A collaboration between scientists at the University of Arizona and the University of Maryland propose to address this deficiency by providing the first fully physically motivated definition of dark matter halos. Based on this, the team will then develop an accurate theoretical model for interpreting data from large galaxy surveys. The Principal Investigator at the University of Arizona will be an active participant in the Tucson Initiative for Minority Engagement in STEM Program, organizing workshops, seminars, and coordinating mentoring activities in the program. The Principal Investigator at the University of Maryland will develop a user-friendly web-interface for the code Colossus to allow for simple visualizations that can be adopted for use in introductory and non-major astronomy courses.This project proposes a radical redefinition of dark matter halos that will enable the construction of percent-level accurate halo models of large-scale structure. The model is built on the inherent dichotomy between particles orbiting a halo and those falling into the halo for the first time. The proposing team has demonstrated that the orbiting and infalling contributions to halo correlation functions roughly correspond to the one- and two-halo terms of the traditional halo model. However, the orbiting/infalling halo model framework is both mathematically simpler and significantly more accurate than the traditional halo model approach. The team will develop the proposed physical halo model framework based on the orbiting/infalling dichotomy. They will then construct halo catalogs based on this revised halo definition for a broad range of simulated cosmologies and redshifts, and use the resulting halo catalogs to calibrate the halo mass function, bias function, and various halo correlation functions. The code and halo catalogs produced by this work will be made publicly available.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.