基于佳木斯66米望远镜的脉冲星辐射特征研究

Pulsar serves as one of the most fascinating objects in the universe. It was found to have lots of curious emission features with various time and spatial scales through observations. However, the origins of these features require further investigations and more peculiar emission features need to be discovered. Pulsar observation relies on sensitive telescopes. As the largest full-steerable radio telescope in our country, JMS 66m will play a key role in this project. We will exploit its advantages of sufficient observing time and use it to receive S-band single pulse signals from a number of strong pulsars. By using the data, we will.1) extract and identify new emission features with the help of phase resolved energy distribution, modulation index and fluctuation spectrum, and new methods like HHT will also be introduced to the time series analysis. .2) further investigate the known peculiar emission behaviors, such as sub-pulse drifting, nulling and mode changing, with the long lasting S-band data, and compare them with previous low frequency observations. .3) extend interstellar scintillation researches to S-band for a number of pulsars with proper DMs, and study the evolutions of secondary spectra of 3 pulsars with clearly detected arcs. .We hope to get a better understanding of pulsar emission processes and the turbulence properties of the interstellar medium through this project.

脉冲星是宇宙中极为奇妙的一类天体。通过观测人们证认出了大量新奇的、具有不同时标和尺度的辐射特征。但是，这些特征及其产生机制还有待深入理解，更多新奇的特征有待进一步发现。脉冲星观测有赖于高灵敏的望远镜。作为当前国内口径最大的全可动射电望远镜，佳木斯66米将为本项目提供重要支撑。我们将充分发挥其观测时长优势，用其收集一系列强脉冲星的S波段单脉冲信号。据此，.1) 提取和证认新奇的辐射特征，主要借助相位分离的能量分布、调制系数和涨落谱等分析手段，并引入HHT等时间序列分析方法；.2) 对已证认的特殊辐射行为，包括子脉冲漂移、消零和模式变换等，用长时间的S波段连续观测数据深入分析，并与低频观测比较研究；.3) 拓展一批DM适中的脉冲星的星际闪烁测量到S波段，研究3颗已探测到清晰弧状结构的脉冲星的二次谱的演化。.我们期望通过该项目得到对脉冲星辐射过程以及星际介质湍动性质的更深入理解。

本项目重点基于佳木斯66米望远镜开展脉冲星辐射特征观测研究。项目中期，FAST建成并开放运行，基于更灵敏的FAST和银道面脉冲星巡天项目开展了脉冲星搜寻和偏振测量。同时还发展了脉冲星的相干辐射理论。.1）佳木斯66米望远镜的脉冲星观测拓展星际闪烁和脉冲消零研究到较高的S波段。新探测到3颗脉冲星的动态谱，发现世界第二例的二次谱的演化，联合已有低频观测检验了星际介质的湍动理论。新发现3颗脉冲星的消零现象，较长的连续观测揭示了脉冲星在不同时标的消零特征，并且提出了系统性开展消零分析的方法。.2）FAST银道面巡天观测新发现了520颗脉冲星，并测量得到650颗脉冲星的偏振脉冲轮廓。新发现的脉冲星在未来将有助于检验脉冲星辐射理论、恒星演化理论和引力理论，并为脉冲星计时阵提供优选目标用于探测引力波。高精度偏振测量结果正被用于精确确定脉冲星的辐射几何、辐射模式、射电辐射区域等物理特征，以及用于研究银河系磁场结构。.3）所建立的脉冲星相干辐射模型预言和解释了部分辐射现象。.通过本项目和相关项目，累积了300多颗脉冲星的长时间S波段观测数据、520颗脉冲星的发现数据、650颗脉冲星的偏振数据和单脉冲数据。这些大量且高灵敏的观测数据为即将开展的大样本脉冲星辐射特征研究和群族分析提供了重要基础。