Astronomers have found a new Einstein cross. This makes four identical images of one distant galaxy visible.
Scientists used the Very Large Telescope to spot the quadruple lens system. The object has been named DESI-253.2534+26.884.
The red dot in the center is an elliptical galaxy. This galaxy has a very strong gravitational field. The light from objects behind the cluster is bent. This has all kinds of consequences. In this way, the image of a galaxy can be enhanced, distorted or stretched. Sometimes it even produces multiple images, for example in the case of this new Einstein cross. Thanks to gravitational lenses, distant, invisible galaxies can become visible.
Due to the expansion of the universe, distant galaxies are redder than nearby galaxies. Yet that kite does not apply to this Einstein cross. The galaxy at the center is much closer to Earth than the leaves of the four-leaf clover. The four images of the distant galaxy appear bluer because there are many young stars in this galaxy. The foreground galaxy in the center consists mainly of old stars and therefore looks redder.
World-famous Hubble photo of the first Einstein Cross
In the paper the authors also briefly look back on the history of Einstein crosses. In 1985, astronomers found the very first Einstein Cross: Huchra’s Lens (G2237 + 0305). This galaxy is named after co-discoverer John Huchra and is located 400 million light-years from Earth. Made in 1990 the Hubble telescope took this now world-famous photo of this Einstein cross. The four leaves are formed by a quasar eight billion light years away. The foreground galaxy is only 400 million from our planet. After Huchra’s Lens, numerous new crosses were found.
What does Einstein have to do with it?
You may wonder: why is such an object called an Einstein cross? This is because an Einstein cross is a perfect example of a gravitational lens. Albert Einstein published the general theory of relativity in 1916 in which he predicted, among other things, that the gravity of a galaxy can bend light, just like a glass lens does. Later this prediction came true.
2023-09-16 14:05:32
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