Distant galaxies lined up in space

The image taken by Japan's Subaru Telescope in Hawaii shows the central part of a rich galaxy cluster 7 billion light-years away. 

The straight line is from the top left to the bottom right

Astronomers face a puzzle in the sky - an image of a distant galaxy cluster that appears as a straight line across the universe. The Japanese Subaru Super Telescope, located on top of an extinct volcano in Hawaii, captured this unusual image.
Astronomers believe that this cosmic alignment has to do with the way these galaxy clusters were assembled. Most of the galaxies in the universe belong to a cluster, and the galaxy clusters form superclusters themselves.
The image taken by Subaru shows the central part of a rich galaxy cluster located 7 billion light-years away. Hundreds of galaxies are visible in a region much more densely populated with galaxies than our region of space. The astronomers were fascinated by the straight line in which these galaxies are arranged, the complete structure goes beyond even the picture. For them it shows that they are witnessing a cluster in its creation process during which it collects galaxies along a chain-like structure that grows into a larger system.
You can also see in the image a large number of blue rainbow-like galaxies. These are galaxies that are in the background whose luminosity is increased due to the gravitational force of the cluster closer to us. By analyzing these images, astronomers will be able to map the mass distribution in the cluster and see what it is going to do to the oddly shaped cluster.