Gravitational Lens
引力透镜
| Since light is bent by a gravity field according to general relativity, there is a possibility of focusing effects like that of a lens when there is a large collection of mass near the path of the light to us. The two brighter objects in the sketch to the right are interpreted as two images of the same quasar, Q0957 +561. The focusing matter is an intervening giant galaxy.
根据广义相对论，光会因重力场而弯曲，因此当有大量质量接近光的路径时，可能会产生类似透镜的聚焦效应。图中右侧的两个较亮的天体被解释为同一类星体Q0957 +561的两个像。聚焦的物质是一个位于中间的巨型星系。 |
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"In this photograph, light from the distant galaxy bends as it passes through the cluster, dividing the galaxy into five separate images. One image is near the center of the photograph; the others are at 6, 7, 8, and 2 o'clock. The light also has distorted the galaxy's image from a normal spiral shape into a more arc-shaped object. Astronomers are certain the blue-shaped objects are copies of the same galaxy because the shapes are similar. The cluster is 5 billion light-years away in the constellation Pisces, and the blue-shaped galaxy is about 2 times farther away." When the amount of bending is analyzed, the required bending mass is greater than can be accounted for from the visible mass of the cluster, so this is another piece of evidence for the existence of dark matter.
在这张照片中，来自遥远星系的光在穿过星团时发生弯曲，将星系分成五个独立的图像。其中一个图像位于照片的中心；其他四个分别位于6点、7点、8点和2点方向。光也使星系的图像从正常的螺旋形状扭曲成一个更弧形的物体。天文学家确定蓝色形状的物体是同一星系的复制品，因为这些形状相似。星团位于仙女座星座，距离地球50亿光年，而蓝色形状的星系则大约远2倍。当弯曲程度被分析时，所需的弯曲质量大于可以由星团可见物质所解释的量，因此这也是暗物质存在的又一证据。
"Though the gravitational light-bending process is not new, Hubble's high resolution image reveals structures within the blue-shaped galaxy that astronomers have never seen before. Some of the structures are as small as 300 light-years across. The bits of white imbedded in the blue galaxy represent young stars; the dark core inside the ring is dust, the material used to make stars. This information, together with the blue color and unusual "lumpy" appearance, suggests a young, star-making galaxy."
尽管引力透镜效应并不是新现象，但哈勃高分辨率图像揭示了蓝形星系内部一些前所未见的结构。其中一些结构的尺寸仅有300光年。嵌入在蓝形星系中的白色斑点代表年轻恒星；环状结构内部的暗核心是尘埃，是制造恒星的材料。这些信息，加上蓝色色调和不规则的外观，表明这是一个正在形成恒星的年轻星系。
"The picture was taken October 14, 1994 with the Wide Field Planetary Camera-2. Separate exposures in blue and red wavelengths were taken to construct this color picture.
Credit: W.N. Colley and E. Turner (Princeton University), J.A. Tyson (Bell Labs, Lucent Technologies) and NASA. "
这张照片于1994年10月14日使用宽场行星照相机-2拍摄。为了构造这张彩色照片，分别拍摄了蓝光和红光的曝光。版权：W.N. Colley和E. Turner（普林斯顿大学），J.A. Tyson（贝尔实验室，Lucent技术）和NASA。
Gravitational lensing has now been observed with a number of galaxies. In a study reported in the Astrophysical Journal in February 2006, Adam Bolton and colleagues at the Harvard-Smithsonian Center for Astrophysics described 19 galaxies that were distorting the images of more distant galaxies that were closely aligned with them. Eight of them were so closely aligned that they bent the light of the more distant galaxy into a ring of light called an Einstein ring. The observations were made by the Hubble Space Telescope, guided toward likely candidates for gravitational lensing by the Sloan Digital Sky Survey.
引力透镜现象现在已经通过多个星系得到了观测。在2006年2月《天体物理学杂志》上的一项研究中，哈佛-史密松天体物理中心的Adam Bolton及其同事描述了19个星系，这些星系使更遥远的星系图像发生了扭曲，这些更遥远的星系与它们有紧密的对齐。其中8个星系对齐得如此紧密，以至于它们将更遥远星系的光弯曲成一个称为爱因斯坦环的光环。这些观测是通过哈勃太空望远镜进行的，该望远镜根据Sloan数字天空调查的可能候选者进行引导。
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