In this Image of the Week there are many galaxies, but the most interesting is probably the one surrounded by four light blue dots, which reminds us of a flower with blue petals. But are these points true? Yes and no… In this image, taken with ESO’s Very Large Telescope (VLT), we see the so-called Einstein Cross.
The four “petals” are images of a distant galaxy hidden behind the orange galaxy in the center. What allows us to detect the light from this hidden object is an interesting phenomenon: the galaxy at the center acts as a gravitational lens, bending the light emitted by the distant galaxy around it. As a result, we see many distorted and magnified images of distant galaxies. In the configuration of these two specific galaxies, the hidden appears as four images around the central galaxy that act as a “lens”, forming a cross-shaped (or flower) pattern called Einstein Cross. So gravitational lensing allows us to discover hidden galaxies that we cannot see.
Observations of this system were made with the Multi Unit Spectroscopic Explorer MUSE instrument installed at the ESO VLT in Chile. MUSE divides the light coming from each point within the observed area into a rainbow or spectrum, providing the astronomical community with a wealth of information about the objects in the field of view. The results of these observations, presented in a new paper led by Aleksandar Cikota of the Gemini Observatory (Chile), show that the distant galaxy is forming stars at a rapid rate (1). Because the light left the galaxy when the universe was about 20% of its current age, studying it provides clues about how galaxies formed in the early universe.
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(1) The expansion of the Universe makes distant galaxies appear redder than if they were closer to us. As such, in this image all four images of distant galaxies appear blue due to the presence of young stars. The lens galaxy in the center is closer to us, but it looks red because it is mostly made up of old stars.
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About the picture
| Identifier: | potw2337a |
| Language: | es-cl |
| Type: | Collage |
| Publication date: | September 11, 2023 at 06:00 |
| Size: | 2001 x 1013 px |
About the thing
| Type: | Early Universe : Galaxy : Type : Gravitationally Lensed |
