Einstein’s theory of general relativity tells us how the curvature of space causes the path of light from a more distant galaxy to bend as the light passes near a massive cluster of galaxies. The cluster of galaxies acts as a lens, magnifying and distorting the light from the more distant galaxy. This often leads to astronomers observing multiple “lensed images” of the distant galaxy. Compared to other commonly observed galaxy clusters, MACS J0416 is more efficient at producing multiple lensed images of background galaxies1. This means that we expect to find a higher than usual number of images for every galaxy lensed by MACS J0416.
The Massive Cluster Survey (MACS) contains a sample of more than 100 galaxy clusters, measured by the ROSAT telescope to be bright in high-energy X-ray light. The goals of the MACS survey are to categorize and better understand distant massive galaxy clusters.
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