Establishing the Fundamental Physics and Interactions of Coherent Radio and Thermal X-ray Emission from Pulsars

脉冲星是快速旋转，高度磁化，非常紧凑的恒星，五十多年前才被发现。 来自太阳的光通常以无线电波或X射线的形式被探测到。 无线电波是从沿着脉冲星磁场线流动的带电等离子体中发射出来的，而X射线则是从非常热的（因此是“热”）表面区域发射出来的，被回流的等离子体加热。 虽然脉冲星射电和X射线辐射的全貌是已知的，但许多细节还有待完全理解。 佛蒙特大学的一个研究小组将开展一项由三部分组成的观测和理论计划，旨在深入了解脉冲星发射机制，并研究银河系的星际磁场。 无线电观测已经或将主要使用甚大天线阵、阿雷西博、LOFAR和绿色银行进行。 使用XMM-牛顿卫星进行了X射线观测。 该计划的第一部分涉及脉冲星无线电发射物理的确认和扩展。 第二部分将把热X射线与无线电发射联系起来。 第三部分将使用脉冲星测量来帮助理解我们银河系平面上的磁场。 本科研究生将广泛参与这些项目，并将获得课堂上根本无法获得的宝贵科学培训。通过对脉冲星磁层的观测解释和计算机建模，天文学家现在了解了电荷电流是如何产生的以及它们在哪里流动，概述了脉冲星无线电发射的广泛机制：它在哪里产生以及部分如何逃逸。 计划中的研究将提高将发射物理学与全球磁层过程联系起来的能力，并为理论家开发带电孤子辐射的物理模型提供所需的特异性。 研究小组还将同时使用X射线和无线电观测具有多种发射状态的类星体，以了解与热X射线发射相关的回流加热如何与无线电发射特性的变化相关联，并将确定未来联合X射线/无线电调查的候选类星体。 银河系磁场的性质、结构和起源只被部分地了解。该项目将包括广泛的分析，现有的脉冲星法拉第旋转测量遥远和微弱的恒星，大大有助于了解磁场在我们的银河系的平面。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

Pulsars are rapidly spinning, highly magnetized, and very compact stars, which were discovered just over fifty years ago. The light from pulsars is usually detected as radio waves or X rays. The radio waves are emitted from charged plasma flowing along the pulsar's magnetic field lines, while the X rays are emitted from very hot (hence "thermal") surface areas, heated by backflowing plasma. While the broad picture of pulsar radio and X-ray emission is known, many of the details are yet to be fully understood. A research team at the University of Vermont will carry out a three part observational and theoretical program aimed at providing insight into pulsar emission mechanisms and studying the Milky Way's interstellar magnetic field. The radio observations have been or will be conducted primarily with the Very Large Array, Arecibo, LOFAR and Green Bank. X-ray observations have been made using the XMM-Newton satellite. The first part of the program involves confirmation and extension of pulsar radio emission physics. The second part will connect thermal X-ray to radio emission. The third part will use pulsar measurements to help to understand the magnetic field in the plane of our Galaxy. Undergraduate research students will be extensively involved in the projects and will receive invaluable scientific training that is simply not available in the classroom.Through observational interpretation and computer modeling of the pulsar magnetosphere, astronomers now understand how charge currents are generated and where they flow, outlining the broad mechanisms of pulsar radio emission: where it is generated and how part of it escapes. The planned study will advance capabilities to relate the emission physics to global magnetospheric processes, and provide the needed specificity for theorists to develop physical models for charged soliton radiation. The research team will also use simultaneous X-ray and radio observations of pulsars with multiple emission states in order to learn how the backflow heating associated with thermal X-ray emission is connected to changes in the radio emission properties, and will identify candidate pulsars for future joint X-ray/radio investigations. The nature, structure, and origin of the Galactic magnetic field is only partially understood. The project will include analyses of extensive, existing pulsar Faraday rotation measurements of distant and faint pulsars to contribute significantly to the understanding of the magnetic field in the plane of our Galaxy.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.