First-Principles Modeling of Pulsar Multi-Wavelength Emission

脉冲星是一种快速旋转的强磁化中子星，发出脉冲多波长辐射，呈现出宇宙中一些最极端的环境。这些物体结合了相对论等离子体物理、超强磁场、非线性量子电动力学和广义相对论的影响。尽管对2000多颗已知脉冲星进行了50多年的观测，但关于它们是如何产生宽带辐射的，仍有许多悬而未决的问题。在这些问题中，射电发射的机制是天体物理学中最著名的未解决问题之一。利用当前的多波长观测覆盖和前所未有的计算能力，圣路易斯华盛顿大学的一个研究小组将利用直接数值模拟来回答这些问题。像脉冲星这样的极端物体是吸引学生和公众好奇心的绝佳话题。对于本科生和研究生来说，研究这些对象可以使他们在分析复杂的物理现象方面得到很好的训练。对于公众来说，这些极端的物体可以唤起他们深深的好奇心，并可能说服更多的人从事与stem相关的活动或从事与物理或天体物理相关的职业。为了实现这种文化影响力，该团队将指导学生，参加圣路易斯的社区活动，并组织一个高能天体物理学暑期学校。这项工作将提供脉冲星发射机制的统一理论模型，直接将等离子体物理过程与观测数据联系起来。该项目将采取双管齐下的方法，以第一性原理等离子体模拟为基础，系统地了解脉冲星物理如何导致观测信号。首先，该团队将研究导致无线电信号和高能伽马射线发射的局部辐射和等离子体微物理。然后，他们将研究脉冲星磁层的整体结构如何决定其多波长光曲线，并开发一个基于所有波长观测数据推断物理性质的模型。这项研究还将为物理学的其他分支提供关键见解：它将告知模型构建者更好地约束中子星内的核状态方程；它将使我们更好地理解这种极端环境下的相对论等离子体物理；它还可以约束标准模型之外的物理，探测暗物质候选粒子的参数空间。该奖项反映了美国国家科学基金会的法定使命，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。

Pulsars, which are rapidly rotating, strongly magnetized neutron stars emitting pulsed multi-wavelength radiation, present some of the universe's most extreme environments. These objects combine the effects of relativistic plasma physics, ultra-strong magnetic fields, nonlinear quantum electrodynamics, and general relativity. Despite more than five decades of observational data on over 2,000 known pulsars, many open questions remain regarding how they produce their broadband radiation. Among these questions, the mechanism of their radio emission is one of the most famous unsolved problems in astrophysics. Leveraging current multi-wavelength observational coverage and unprecedented computing power, a research team at Washington University in St. Louis will work toward answering these questions using direct numerical simulations. Extreme objects such as pulsars are excellent topics to capture the curiosity of students and the general public. For undergraduate and graduate students, studying these objects gives them excellent training in analyzing complex physical phenomena. For the public, these extreme objects can conjure their deep curiosity and may persuade more people to engage in STEM-related activities or pursue a career related to physics or astrophysics. To achieve this cultural influence, the team will mentor students, participate in community events in St. Louis, and organize a high energy astrophysics summer school.This work will provide a unified theoretical model of the pulsar emission mechanism, directly connecting plasma physics processes with observational data. The project will take a two-pronged approach based on first-principles plasma simulations to systematically understand how pulsar physics leads to observational signals. First, the team will study local radiation and plasma microphysics that lead to the emission of radio signals as well as very high-energy gamma-rays. Then they will study how the global structure of the pulsar magnetosphere determines its multi-wavelength light curve and develop a model to infer physical properties based on observational data at all wavelengths. The study will also provide key insights into other branches of physics: it will inform model builders to better constrain the nuclear equation of state within a neutron star; it will give us better understanding of relativistic plasma physics in such extreme environments; it can also constrain physics beyond the Standard Model and probe parameter spaces for dark matter particle candidates.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.