Shape and Size of Pulsar Emission Regions via Statistics of Scattering

本项目将利用星际散射作为透镜，研究脉冲星发射区的大小和形状。 它将得出船帆座脉冲星发射区的大小和伸长作为脉冲相位的函数，提供数百公里大小的图像或短片，并提高对脉冲星发射的理解。 该项目将推进对散射源信号的数学描述，并应导致改进散射器。 主要工作包括：（1）安装软件相关器，研究和校正去色散、数字化和脉冲星选通的影响;（2）改进和扩展小扰动源的强度和干涉可见度的数学模型，包括噪声的影响;（3）测量Vela脉冲星的源大小、伸长和位置角随脉冲相位的变化; 4）测量，或至少设定限制，旧的，慢的恒星的发射区域的大小。这项工作将形成研究生论文的主体，并将包括通过论文和暑期项目的本科物理专业。 该项目还将通过一个周末科学项目，向当地高中学生介绍声音到电的转换，以及计算机信号处理，以补充耳朵和大脑破译声音的能力。

This project will study the sizes and shapes of pulsar emission regions, using interstellar scattering as a lens. It will derive the sizes and elongations of the emission region of the Vela pulsar as a function of pulse phase, providing images or a short movie over sizes of a few hundred kilometers, and improving understanding of pulsar emission. The project will advance the mathematical description of signals from a scattered source, and should lead to improvements in correlators. The work includes 1) installing a software correlator to study and correct for effects of de-dispersion, digitization, and pulsar gating; 2) improving and extending mathematical models for the intensity and interferometric visibility of small scintillating sources, including the effects of noise; 3) measuring the variation of source size, elongation, and position angle as a function of pulse phase, for the Vela pulsar; and 4) measuring, or at least setting limits on, the sizes of emission regions of older, slower pulsars.This work will form the bulk of a graduate student's thesis, and will include undergraduate physics majors via theses and summer projects. Through a weekend science program, the project will also introduce local high-school students to conversion of sound to electricity and back, and to signal processing by computer to supplement the ear and brain in deciphering sound.