First-Principles Modeling of Pulsar Multi-Wavelength Emission

脉冲星是一种快速旋转、强烈磁化的中子星，发射脉冲多波长辐射，呈现出宇宙中一些最极端的环境。这些天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效应。尽管对2000多颗已知脉冲星进行了50多年的观测数据，但关于它们如何产生宽带辐射仍有许多悬而未决的问题。在这些问题中，它们的射电发射机制是天体物理学中最著名的悬而未决的问题之一。利用目前的多波长观测覆盖范围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致力于使用直接的数值模拟来回答这些问题。像脉冲星这样的极端物体是激发学生和公众好奇心的绝佳话题。对于本科生和研究生来说，研究这些对象可以很好地训练他们分析复杂的物理现象。对于公众来说，这些极端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相关的活动或追求与物理或天体物理相关的职业。为了实现这种文化影响，该团队将指导学生，参加圣路易斯的社区活动，并组织高能天体物理暑期学校。这项工作将提供脉冲星发射机制的统一理论模型，将等离子体物理过程与观测数据直接联系起来。该项目将采取基于第一原理等离子体模拟的双管齐下的方法，系统地理解脉冲星物理是如何导致观测信号的。首先，该团队将研究导致无线电信号和超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全球结构如何决定其多波长光曲线，并开发一个模型，根据所有波长的观测数据推断物理特性。这项研究还将为物理学的其他分支提供关键的见解：它将使模型建造者更好地约束中子星内的核状态方程；它将使我们更好地了解这种极端环境中的相对论等离子体物理学；它还可以约束超出标准模型的物理并探测暗物质粒子候选者的参数空间。该奖项反映了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。

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.