上海天马射电望远镜和美国甚长基线干涉阵脉冲星联合观测研究

It is known to all that the pulsar observation is very important for the astrophysics research and practical applications. Both the single dish telescope and the Very Long Baseline Interferometry (VLBI) are important tools to do pulsar studies. Each of them has its own advantages, and they are auxiliary to each other. Under the support of this fund, we will do astrometry measurements on two high declination pulsars, PSR B0458+46 and PSR B2334+61, and monitor their timing properties. The pulsar astrometry will be carried out with the VLBI which consists of Shanghai Tian Ma Radio Telescope (TMRT) and the Very Long Baseline Array (VLBA) across the USA. The participation of the TMRT will overcome the limitation that the resolution along the East-West direction is very poor in the observation of high declination object with only VLBA telescopes. The timing observation of these two pulsars are carried out with the TMRT. The main research objectives are as follows: ①studying how to tune the compatibility of the VLBI system of TMRT with the VLBA system and the related methods in the data reduction process; ②studying the method of eliminating the residual phase fluctuation caused by ionosphere effects with the in-beam or almost in-beam calibrator; ③measuring the distance and the velocity of the target pulsars with VLBI accurately; ④calculation the dynamic age of target pulsars and inferring their initial rotation period; ⑤clarifying the association of these two pulsars with the supernova remnants around them; ⑥studying the improvement of the pulsar timing observation by incorporating the astrometry parameters obtained with the VLBI measurement and doing a further discussion about timing properties of these two pulsars.

脉冲星观测研究具有重要的物理意义和应用价值。单天线和甚长基线干涉仪（VLBI）都是脉冲星观测研究的重要工具，二者相辅相成。本项目将对两颗高赤纬脉冲星PSR B0458+46和PSR B2334+61开展VLBI测量和到达时间（Timing）监测：VLBI测量由天马望远镜和甚长基线干涉阵（VLBA）组成的VLBI网完成，天马望远镜的加入将克服VLBA观测高赤纬天体东西方向分辨率低的缺点；Timing监测由天马望远镜完成。研究内容如下：①研究天马望远镜和VLBA脉冲星联合观测兼容性的解决方法及数据处理技巧；②研究利用“同波束”或“准同波束”参考源消除VLBI脉冲星观测中残余电离层相位扰动的有关方法；③利用VLBI精确测定目标脉冲星距离和速度；④计算目标脉冲星动力学年龄并推算其初始自转参数；⑤认证目标脉冲星与周围超新星遗迹成协性；⑥研究VLBI测量对脉冲星Timing改善情况及Timing特性。

脉冲星做为一类集强引力、强磁场、强电场于一身的特殊天体，其观测研究具有重要的物理意义和应用价值。过去的脉冲星观测主要采用单天线进行。但是，单天线和甚长基线干涉仪（VLBI）都是脉冲星观测研究的重要工具，而且二者相辅相成。近些年，随着VLBI技术以及数据相关处理技术的进展，脉冲星的VLBI观测逐步开展起来。本项目对两颗高赤纬脉冲星PSR B0458+46和PSR B2334+61开展VLBI测量和到达时间（Timing）监测：VLBI测量由天马望远镜和甚长基线干涉阵（VLBA）组成的VLBI网完成，天马望远镜的加入克服了VLBA观测高赤纬天体东西方向分辨率低的缺点；Timing监测由天马望远镜完成。项目按计划顺利开展，具体开展了如下研究：①研究天马望远镜和VLBA脉冲星联合观测兼容性的解决方法及数据处理技巧；②研究利用“同波束”或“准同波束”参考源消除VLBI脉冲星观测中残余电离层相位扰动的有关方法；③利用VLBI精确测定目标脉冲星距离和速度；④计算目标脉冲星动力学年龄并推算其初始自转参数；⑤认证目标脉冲星与周围超新星遗迹成协性；⑥研究VLBI测量对脉冲星Timing改善情况及Timing特性。经过研究，解决了天马射电望远镜和VLBA脉冲星联测的兼容性；测得B0458+46和B2334+61的自行速度分别为72.64+/-3.12 km/s和47.35+/-2.84 km/s，距离分别为1.45+/-0.16 kpc和1.94+/-0.21 kpc；通过计算特征年龄等参数，排除了B0458+46和其周围超新星遗迹的成协性，确认了B2334+61和G114.3+0.3的成协性；目标脉冲星的Timing观测获得成功，VLBI测量结果的应用是的其精度进一步提高。本项目为后续研究积累了丰富经验。