标题： ALFA首次观测结果与自然导星和激光导星 显示英文标题

标题： First Observational Results from ALFA with Natural and Laser Guide Stars

摘要： 安装在卡拉阿托3.5米望远镜上的钠激光导星自适应光学系统ALFA，已经进入了一个密集的优化阶段。 本文中使用自然导星的观测表明，对于明亮的恒星（V~<8），现在已经可以达到超过60%的K波段Strehl比，并且能够轻松分辨出处于望远镜衍射极限的双星。 在更典型的使用情况下，可以在宽视场（~2'）范围内实现10-15%的Strehl比；目前的极限星等为V~<12.5。 我们还展示了部分首次在衍射极限尺度上的光谱分析，表明我们能够区分分离仅0.26''的双星光谱。 我们的最后一组结果涉及Abell星系团，其中包括利用激光导星作为参考对一个星系进行的校正。 尽管激光仍存在一些困难，但到目前为止，我们最好的结果是Abell 262中的星系UGC 1347。 在距离41''的恒星上校正倾斜-倾斜，并在激光上校正更高阶的像差，我们实现了峰值强度增加2.5倍，以及FWHM从1.07''减少到0.40''。 预计在未来6个月及更长时间内将取得进一步的重大进展。 显示英文摘要

摘要： The sodium laser guide star adaptive optics system ALFA, which is installed at the Calar Alto 3.5-m telescope, has been undergoing an intensive optimisation phase. Observations using natural guide stars that are presented in this paper, show that for bright stars (V~<8) it is now possible to reach K-band Strehl ratios in excess of 60% and to easily resolve binaries at the diffraction limit of the telescope. In more typical usage Strehl ratios in the range 10-15% can be achieved over a wide field (~2'); and the limiting magnitude is currently V~<12.5. We also present some of the first spectroscopy at diffraction limited scales, showing we are able to distinguish spectra of binary stars with a separation of only 0.26''. Our last set of results are on Abell galaxy clusters, including a correction on a galaxy using the laser guide star as the reference. There are still a number of difficulties associated with the laser, but our best result to date is of the galaxy UGC 1347 in Abell 262. Correcting tip-tilt on a star 41'' away and higher orders on the laser, we achieved in increase in peak intensity of 2.5, and a reduction in FWHM from 1.07'' to 0.40''. It is expected that further significant advances will be made in the next 6 months and beyond.