重力的笑容
(原标题: Gravity's Grin)
2022-05-11
浏览次数: 17
爱因斯坦在100多年前发表的广义相对论预言了引力透镜现象。通过钱德拉和哈勃太空望远镜的x射线和光学图像数据，我们可以看到这些遥远的星系如此异想天开的样子。这个星系群被称为柴郡猫星系群，它的两个大椭圆星系被弧线框起来。这些弧线是遥远背景星系的光学图像，被前景星系群的引力质量总分布透镜化。当然，引力质量主要是暗物质。这两个巨大的椭圆“眼睛”星系代表了它们各自星系群中最亮的成员，它们正在合并。它们的相对碰撞速度接近1350公里/秒，将气体加热到数百万度，产生紫色的x射线光。对星系群合并感到好奇吗？柴郡猫群在大熊座咧嘴笑着，距离我们大约46亿光年。
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Albert Einstein's general theory of relativity, published over 100 years ago, predicted the phenomenon of gravitational lensing. And that's what gives these distant galaxies such a whimsical appearance, seen through the looking glass of X-ray and optical image data from the Chandra and Hubble space telescopes. Nicknamed the Cheshire Cat galaxy group, the group's two large elliptical galaxies are suggestively framed by arcs. The arcs are optical images of distant background galaxies lensed by the foreground group's total distribution of gravitational mass. Of course, that gravitational mass is dominated by dark matter. The two large elliptical "eye" galaxies represent the brightest members of their own galaxy groups which are merging. Their relative collisional speed of nearly 1,350 kilometers/second heats gas to millions of degrees producing the X-ray glow shown in purple hues. Curiouser about galaxy group mergers? The Cheshire Cat group grins in the constellation Ursa Major, some 4.6 billion light-years away.