Investigation of X-ray Objects with Astro-D and ROSAT

日本第四颗X射线天文卫星Astro-D于1993年2月20日成功发射，并被命名为ASCA。ASCA的关键部件在轨道上相继开启，并于1993年4月开始观测工作。4月至10月进行了性能验证观测，不仅对科学仪器的性能进行了验证，还对科学能力进行了验证。之后，根据世界天文学家的建议开始了客机观测。ASCA是第一颗能够在0.5至12keV的宽能量范围内对X射线天空成像的X射线天文卫星，尽管X射线望远镜的图像大小约为1角分半高宽。ASCA的灵敏度远好于非成像仪器，如Ginga上的大面积计数器。此外，ASCA首次将该CCD相机送入轨道，并具有出色的光谱分辨率。另一方面，在轨运行约4年的德国X射线天文卫星ROSAT在0.5keV以下的能量范围内比ASCA具有更好的成像能力和更高的灵敏度。ASCA和ROSAT是相辅相成的，在业绩核查期间和来宾观察期都同时进行了几次观测。ROSAT进行的全天测量的结果也对ASCA的几次指向观测有用。这些合作的成果在1994年3月由空间和宇航科学研究所在东京市立大学举行的“X射线天文学的新地平线--来自ASCA的第一个结果”的国际研讨会上作了介绍。

The Japan's fourth X-ray astronomy satellite, Astro-D was successfully launched on Feb. 20, 1993, and was named ASCA. The key elements of ASCA were successively turned on in orbit and it started its observatory work since April, 1993. The performance verification observations were done from April to October and not only the performance of the scientific instruments but also the scientific capability wes verified. After then, the guest observations based on proposals by astronomers in the world started.ASCA is the first X-ray astronomy satellite capable of imaging the X-ray sky in the wide energy range over 0.5 to 12 keV, although the image size of the X-ray telescope is approximately 1 arcminutes FWHM. The sensitivity of ASCA is much better than that of non-imaging instruments such as the large area counters on board Ginga. Furthermore, the CCD camera was carried into orbit for the first time by ASCA and has an outstanding spectral resolution. On the other hand, the German X-ray astronomy satellite ROSAT which has been in orbit for about four years has much better imaging capability and higher sensitivity in the energy range below 0.5 keV than ASCA. ASCA and ROSAT are complementary to each other and several simultaneous observations were already performed both in the performance verification period and the guest observation period. The results of the all sky survey done by ROSAT have also been useful to several ASCA pointing observations. The yields of these collaborations were presented in the international symposium "New Horizon in X-Ray Astronomy-First Rsults from ASCA-" held at the Tokyo Metropolitan University by Institute of Space and Astronautical Science in March, 1994.