Modeling Emission and Particle Acceleration in Magnetars

磁星发射和粒子加速建模

• 批准号: 0607651
• 负责人: Matthew Baring
• 金额: $ 27.31万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0607651&HistoricalAwards=false
• 关键词: Modeling; Emission; Particle; Acceleration; Magnetars

The research to be conducted centers on the properties of magnetars - a subclass ofneutron stars with magnetic fields of strength in excess of the critical quantumelectrodynamic threshold. Here, a series of projects will be carried out aimed at helpinganswer several questions of current scientific interest. Included are: (1) What is theemission mechanism of magnetars in quiescence? (2) What controls the spectrum of softgamma ray repeater (a type of magnetar) flares? (3) How is the energy of activity ofmagnetars tapped in their magnetospheres? And (4) physically, how and why aremagnetars different from conventional pulsars? Three general avenues of research will beundertaken, each with associate subprojects. The first is an investigation of resonantscattering in shaping the spectrum of anomalous x-ray pulsar spectra by refiningcalculations of resonant Compton scattering in ultra strong magnetic fields and theupscattering of thermal surface photons by magnetospheric electrons. In the second, theroles of resonant Compton scattering and photon splitting in the burst spectra of softgamma-ray repeaters will be explored. This includes developing dispersion and selectionrules for photon splitting in ultra strong magnetic fields. Finally, a generalized formalismfor stochastic, diffusive, gyroresonant acceleration of particles due to magneticturbulence superposed upon the global magnetar field structure will be developed. Amajor emphasis will be determining the shape of the non-thermal distribution and howthe maximum energy of acceleration couples to environmental parameters, which will inturn lead to useful observational diagnostics on the emission region.A graduate student will be employed and trained and will be an integral part of the work.This student will also be exposed to undergraduate pedagogy by teaching at least twolectures per year on neutron stars. Undergraduates are expected to contribute as wellthrough small, well defined tasks. Results of this work will be presented to the publicthrough outreach activities at local high schools and through the Houston AstronomicalSociety.

这项研究将集中在磁星的特性上，磁星是中子星的一个子类，其磁场强度超过了临界量子电动力学阈值。在这里，将开展一系列旨在帮助回答当前科学兴趣的几个问题的项目。包括：(1)磁星在静止状态下的发射机制是什么？(2)是什么控制了软伽马射线中继器（一种磁星）耀斑的光谱？(3)磁星的活动能量是如何在它们的磁球中被利用的？(4)从物理上讲，磁星与传统脉冲星是如何以及为什么不同的？将进行三个一般的研究途径，每个途径都有相关的子项目。首先，通过改进超强磁场中的共振康普顿散射和磁层电子对热表面光子的上散射的计算，研究了共振散射在形成异常x射线脉冲星光谱中的作用。第二章探讨了共振康普顿散射和光子分裂在软伽马射线中继器突发光谱中的作用。这包括开发在超强磁场中光子分裂的色散和选择规则。最后，我们将推导出叠加在全球磁场结构上的磁湍流引起的随机、扩散、回旋共振粒子加速度的广义形式。一个主要的重点将是确定非热分布的形状以及加速度的最大能量如何与环境参数耦合，这将导致对发射区域有用的观测诊断。研究生将被雇用和培训，并将成为工作的组成部分。该学生还将通过每年至少讲授两次关于中子星的讲座来接触本科教学。本科生也应该通过小而明确的任务做出贡献。这项工作的结果将通过当地高中和休斯顿天文学会的外展活动向公众展示。