韦伯望远镜拍摄到的壮观爱因斯坦环
A dramatic Einstein ring seen by Webb

原始链接: https://phys.org/news/2025-04-einstein-webb.html

广义相对论预言了光线会因引力而弯曲,这在1919年日食期间对星光偏转的观测中得到了证实。这种现象被称为引力透镜,当更近的星系位于光路中时,它会扭曲并放大来自遥远星系的光线。一个特别引人注目的例子是爱因斯坦环,完美的对齐会在前景星系周围形成一个光环。虽然爱因斯坦认为这种效应不可观测,但现代望远镜已经发现了许多例子。詹姆斯·韦伯太空望远镜 (JWST) 最近捕捉到一个令人惊叹的爱因斯坦环,展示了一个遥远的螺旋星系被SMACS J0028.2-7537星团内一个前景椭圆星系透镜化。这个近乎完美的环突出了引力透镜效应以及天文美景对观测者位置的依赖性。

一篇Hacker News关于韦伯望远镜拍摄的爱因斯坦环图像的讨论总结如下: 讨论围绕韦伯望远镜拍摄的一张爱因斯坦环图像展开,澄清了这张图像是韦伯与哈勃望远镜数据合成的结果。用户们讨论了引力透镜效应,确认中央模糊的椭圆星系充当了透镜,放大了并扭曲了其背后的螺旋星系。中央明亮的光点是椭圆星系的核心,周围弥散的光晕也是前景星系的一部分。一位用户质疑为什么图像中没有通常在韦伯望远镜图像中恒星周围看到的衍射峰。答案是:衍射峰通常只出现在最亮的恒星周围。由于观测到的星系极其暗淡,因此衍射不可见。另一位用户提到可以使用这种现象来检验暗物质理论。
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原文

One of the first verified predictions of general relativity is the gravitational deflection of starlight. The effect was first observed in 1919 during a total solar eclipse. Since stars appear as points of light, the effect is seen as an apparent shift in the position of stars near the eclipse. But the effect happens more generally.

If a distant galaxy is obscured by a closer one, some of the distant light is gravitationally lensed around the closer galaxy, giving us a warped and distorted view of the faraway stars. This effect can also magnify the distant galaxy, making its light appear brighter, and we have used this effect to observe some of the most distant stars in the universe.

But perhaps the most beautiful effect of gravitational lensing is what's known as an Einstein Ring. This is where the is so perfectly centered behind the closer galaxy that its light is distorted into a circle of light. Einstein was aware of the effect but said in 1936 that "there is no hope of observing this phenomenon directly." But as brilliant as Einstein was, he couldn't imagine the power of modern telescopes.

We have now found dozens of Einstein rings, and one of the more beautiful examples was recently found by JWST, as seen in the image above. The close galaxy in the foreground is an that's part of a large cluster known as SMACS J0028.2-7537. The more colorful galaxy warped around it is a similar to the Milky Way. It is billions of years more distant, but perfectly aligned to create the almost perfect ring.

Of course, this image is only possible because of our vantage point. Astronomers in other galaxies wouldn't catch such a wondrous image. Yet another astronomical example of how beauty is not only in the eye of the beholder, but also where that beholder is.

Citation: A dramatic Einstein ring seen by Webb (2025, April 1) retrieved 2 April 2025 from https://phys.org/news/2025-04-einstein-webb.html

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