Japan-U. K. Collaboration in X-ray Astronomy Research with the Scientific Satellite "Ginga"

自1987年2月5日发射以来，Ginga卫星在轨道上停留了4年零9个月，1991财政年度成为其任务寿命的结束。Ginga的轨道继续衰落，直到1991年10月30日与卫星进行了最后一次联系。据信，银加于11月1日左右重新进入大气层。在这种情况下，两名日本科学家曾三次访问英国，两名英国科学家也曾三次访问日本。本财政年度的主要合作成果包括以下三项：(1)在银杏任务生命周期的最后阶段，双方科学家就银杏行动密切合作。特别是，作为Ginga的主要仪器的英日联合实验大面积正比计数器已经进行了详细的校准，以证明其性能在整个任务生命周期中保持不变。(2)Ginga的全部数据同时存储在日本和英国，将继续对全世界具有宝贵的科学价值。因此，讨论了建立一个适当的计划，使这些档案数据向公众开放，特别是向其他国家的科学家开放。(3)对几个研究主题进行了联合数据分析，随后编写了联合论文。主题包括宇宙X射线背景、活动星系核、X射线脉冲星、发射白矮星的X射线等。

The fiscal year of 1991 has become the end of mission life of the Ginga satellite, which stayed in the orbit for 4 years and 9 months since the launch on February 5 1987. The orbit of Ginga continued to decay, until October 30 1991 when the last contact was made with the satellite. It is believed that Ginga re-entered the atmosphere on November 1 or so. Under these circumstances, two scientists from Japan visited the United Kingdom on three occasions, and two UK scientists visited Japan on three occasions as well. Principal results of collaboration in the present fiscal year include the following three items.(1)The scientists from, both parties closely collaborated on the Ginga operation during the last phase of its mission life. In particular, the Large Area Proportional Counter, a UK-Japan joint experiment serving as the main instrument of Ginga, has been calibrated in detail to demonstrate that its performance stayed constant during the entire mission life.(2)The entire Ginga data are stored both in Japan and UK, and will continue to be of precious scientific valuable for the entire world. Discussion was therefore made to establish an appropriate scheme to make these archival data open to public, especially to scientists of other countries.(3)Joint data analysis was made on several research topics, followed by preparations of joint papers. The topics include cosmic X-ray background, active galactic nuclei, X-ray pulsars, X-ray emitting white dwarfs, and so on.