87颗南天区射电源的高灵敏度天体测量  

High sensitivity astrometry of 87 radio sources in the southern hemisphere

作　　者：吴德 舒逢春[1,3] 甘江英 何旋[1,2,3] 黄逸丹 WU De;SHU FengChun;GAN JjiangYing;HE Xuan;HUANG YiDan(Shanghai Astronomical Observatory,Chinese Academy of Sciences,Shanghai 200030,China;University of Chinese Academy of Sciences,Beijing 100049,China;Shanghai Key Laboratory of Space Navigation and Positioning Techniques,Shanghai 200030,China)

机构地区：[1]中国科学院上海天文台,上海200030 [2]中国科学院大学,北京100049 [3]上海市空间导航与定位技术重点实验室,上海200030

出　　处：《中国科学：物理学、力学、天文学》2023年第4期99-111,共13页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家自然科学基金(编号:12073065,U2031212)资助项目。

摘　　要：国际天球参考架(International Celestial Reference Frame,ICRF)由河外射电源的精确位置实现.针对参考射电源在南天区数量偏少、位置精度偏低的问题,本文利用包括中国四个甚长基线干涉测量(Very Long Baseline Interferometry,VLBI)台站在内的亚太区域网首次开展了南天区射电源的高灵敏度天体测量实验.在[-90°,-30°]赤纬范围内的87颗目标射电源中,45颗已有少量天体测量数据,但位置精度较低,其余42颗从未进行过天体测量观测.观测实验的时间跨度为2015–2021年,自主完成了VLBI观测纲要编制、相关处理、相关后处理和天体测量参数解算,获得了87颗目标射电源的6471个观测量.综合解算结果显示,目标射电源中0448-392的位置精度最高,达到了0.14 mas.射电源实测相关流量密度结果显示,在X和S波段都小于0.3 Jy的射电源有58颗,占到了总数的67%,显示了观测实验的高灵敏度天体测量能力.本文的观测数据为24颗新的ICRF3射电源贡献了1306个观测量,其中13颗射电源是我们首次观测的,此外还有29颗射电源的1779个观测量将用于下一代国际天球参考架的构建.The International Celestial Reference Frame(ICRF)is established and maintained based on extragalactic radio sources using very long baseline interferometry(VLBI)technology.Because of the fewness and low positional accuracy of reference radio sources in the southern celestial hemisphere,we performed high-sensitivity astrometry experiments for the first time using the Asia Pacific regional network,including four VLBI stations in China.Among the target radio sources,45 have a small amount of astrometric data,but the positional accuracy is poor,and the remaining 42 have no historical astrometric observations.The experiments were performed from 2015 to 2021.We independently completed the VLBI scheduling,data correlation,postprocessing,and astrometric parameter estimations and obtained 6471 observables of 87 target radio sources in the southern celestial hemisphere[-90°,-30°].The global solution results show that the position accuracy of 0448-392 in the target radio source is the highest,reaching 0.14,and its right ascension and declination accuracy are 0.14 and 0.07 mas,respectively.The measured correlated flux densities of radio sources show that 58 have a spectral flux density of less than 0.3 Jy in X-and S-bands,accounting for 67%of the total,demonstrating high-sensitivity astrometric capabilities.Our observational data contributed 1306 observables of 24 new ICRF3 sources,including 13 sources first detected in our experiments.In addition,1779 observables of 29 radio sources will be used to construct the next generation ICRF.

关 键 词：VLBI 天球参考架 射电天体测量 相关流量密度 位置精度 

分 类 号：P228.6[天文地球—大地测量学与测量工程]