Numerical Simulations with Self-Interacting Dark Matter

该奖项资助了加州大学欧文分校的詹姆斯·布洛克教授的研究活动。布洛克教授的研究旨在通过超级计算机模拟来探索暗物质的本质。暗物质是科学界最深层次的谜团之一。它约占宇宙中星团物质的85%，但其基本性质尚不清楚。暗物质的存在提供了最有力的证据之一，证明我们对自然的理解仍然不完整。目前最流行的观点是，暗物质是由与自身(以及与正常物质)弱相互作用的单个粒子组成的，但这个模型面临着在星系尺度上重现观测的一些困难。一个耐人寻味的解决方案是，暗物质更加复杂，有它自己的一套强烈的自我相互作用，可能类似于组成可见世界的粒子。该奖项将支持对星系形成的超级计算机模拟，包括标准暗物质和更复杂的暗物质，以确定星系观测是否提供暗物质自我相互作用的证据。因此，这一领域的研究通过促进科学在其最基本的方向之一--发现和理解宇宙--的进步，促进了国家利益。此外，模拟代码和分析软件将公开，作为该项目的一部分，布洛克教授将指导研究生、本科生和高中生，为这些年轻人提供数学、计算和数据挖掘培训，这些培训将在资助期过后很久为他们和他们的社区带来宝贵的资产。布洛克教授还将就这项研究进行公开演讲。更严格地说，布洛克教授将使用一套模拟程序来提供迄今对暗物质自相互作用截面得出的最准确和最稳健的约束，并确定一旦包括重子的现实处理，自作用暗物质(SIDM)模型是否比标准冷暗物质模型提供了更好的数据匹配。这项工作将包括1)对单个星系和合并星系团的聚焦、理想化模拟；2)宇宙学模拟；以及3)对SIDM框架内的星系形成进行全面的流体动力学模拟。这项工作建立在现有的和经过良好测试的代码基础上，并将涉及运行具有速度无关、各向同性、能量交换截面的模型，以及具有速度相关和非各向同性散射中更复杂行为的模型。

This award funds the research activities of Professor James Bullock at the University of California, Irvine.Professor Bullock's research aims to explore the nature of dark matter using supercomputer simulations. Dark matter stands among the deepest mysteries in science. It makes up some 85% of the clustering matter in the universe, yet its fundamental nature remains unknown. The existence of dark matter provides one of the strongest pieces of evidence that our understanding of nature remains incomplete. The most popular idea at this time is that the dark matter is made of a single particle that interacts only weakly with itself (and with normal matter), but this model faces some difficulties reproducing observations on the scales of galaxies. An intriguing solution is that the dark matter is more complex, with its own set of strong self-interactions, analogous, perhaps, to the particles that make up the visible world. This award will support supercomputer simulations of galaxy formation including both standard dark matter and more complex dark matter to determine whether or not galaxy observations provide evidence that dark matter is self-interacting. As a result, research in this area advances the national interest by promoting the progress of science in one of its most fundamental directions: the discovery and understanding of the universe. Moreover, the simulation codes and analysis software will be made public and Professor Bullock will mentor graduate students, undergraduate students, and high-school students as part of this project, providing these young people with mathematical, computational, and data-mining training that will be a valuable asset for them and their communities well past the funding period. Professor Bullock will also give public lectures on this research.More technically, Professor Bullock will use a suite of simulations to provide the most accurate and robust constraints yet derived on the dark matter self-interaction cross-section and to determine whether or not self-interacting dark matter (SIDM) models provide a better match to data than standard cold dark matter once realistic treatments of baryons are included. The work will include 1) focused, idealized simulations of individual galaxies and merging galaxy clusters; 2) cosmological simulations; and 3) full hydrodynamic simulations of galaxy formation set within the SIDM framework. This work builds upon an existing and well-tested code, and will involve running models with velocity-independent, isotropic, energy-exchange cross-sections as well as models with more complex behavior in velocity-dependence and non-isotropic scattering.