乌鲁木齐天文站建立脉冲星相干消色散观测系统
Pulsar Coherent De-dispersion System in the Urumqi Observatory
-
摘要: 脉冲星发射的辐射信号经过星际介质到达观测天线的过程中,存在色散效应。该效应导致有一定带宽脉冲信号的不同频率成份到达天线时间有延迟,影响对脉冲星的观测。消色散技术是脉冲星观测的关键技术,它对脉冲星观测系统的灵敏度和观测精度至关重要。脉冲星相干消色散过程是:通过对观测信号进行Nyquist采样,对采样数据做傅立叶变换,变换后的频域信号与星际介质Chirp函数乘积,然后再做逆傅立叶变换回时域,得到消色散后的时域信号。乌鲁木齐天文站依托现有的南山25m射电望远镜和VLBI记录终端MK5A系统,自行开发的相干消色散处理软件(Linux操作系统下C语言调用MPI库)和4节点机群系统,建立了脉冲星相干消色散观测系统。Abstract: Pulsar coherent de-dispersion experiment was carried out by using the 25m Nanshan radio telescope in the Urumqi Observatory.It uses a dual polarization receiver operating at 18cm and a VLBI back-end, Mark5A.The data processing system is based on a C program on the Linux and a 4-node Beowulf cluster.A high quality data acquisition system and a clusterwith more processors are needed to build an on-line pulsar coherent de-dispersion system in the future.
下载: