本帖最后由 gohomeman1 于 2009-9-25 01:34 编辑
Abell 370: Galaxy Cluster Gravitational Lens
引力透镜星系团 阿贝尔 370（Abell370）
Credit: NASA,ESA, and the Hubble SM4 ERO Team & ST-ECF
版权：美国宇航局，欧洲空间局，哈勃第4次维护任务前期观测团队，以及太空望远镜—欧洲协调委员会
Explanation:
What is that strange arc?While imaging the cluster of galaxies Abell 370, astronomers had noted an unusual arc to the right of many cluster galaxies. Although curious, one initial response was to avoid commenting on the arc because nothing like it had ever been noted before. In the mid-1980s, however, better images allowed astronomers to identify the arc as a prototype of a new kind of astrophysical phenomenon --the gravitational lens effect of entire cluster of galaxies on background galaxies.
本图说明：这个奇特的弧是什么？天文学家在审视星系团Abell 370图像时，就注意到右方许多星系旁的不寻常的弧。对此奇异天象，（天文学家）最初的反应是回避此问题，因为以前从未见过类似现象。在上世纪80年代中叶，随着更好的图像被获得，天文学家鉴定此弧为一类新的天体物理学现象——（前景的）整个星系团对背景星系（星光）的引力透镜效应。
Today, we know that this arc actually consists of two distorted imagesof a fairly normal galaxy that happened to lie far behind the hugecluster. Abell 370's gravity caused the background galaxies' light --and others -- to spread out and come to the observer along multiple paths, not unlike a distant light appears through the stem of a wine glass. In mid-July, astronomers used the just-upgraded Hubble Space Telescope to image Abell 370 and its gravitational lens images in unprecedented detail. Almost all of the yellow images pictured above are galaxies in the Abell 370 cluster.An astute eye can pick up many strange arcs and distorted arclets, however,that are actually images of more distant galaxies.
今天，我们知道这个弧实际上由一个遥远的正常星系的2个扭曲图像构成，此星系恰巧位于巨大的星系团后的远方。Abell 370星系团的巨大引力使背景星系的星光和其他辐射被展开并沿着多重路径到达观测者，就像我们透过高脚酒杯看远方的光源一样。今年7月中旬，天文学家用刚刚升级完毕的哈勃太空望远镜拍摄了Abell 370星系团和其引力透镜效应，获得了前所未有的细节图像。上图中，绝大部分的黄色天体都是Abell 370星系团的成员。眼光锐利的人可以发现更多的奇异光弧和扭曲的小弧，它们其实都是更遥远的星系图像。 （arclet这个词感谢q5968661兄弟的指正。——gohomeman1注）
Studying Abell 370 and its images gives astronomers a unique window into the distribution of normal and dark matter in galaxy clusters and the universe.
对Abell 370星系团图像的研究给予天文学家一个独特视角，用以研究宇宙、星系团中普通物质和暗物质的分布。
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