The Hubble Space Telescope captured an image of the galaxy cluster ACO S520, containing several interesting astronomical finds, including a ring-shaped galaxy and a pair of bright stars. Astronomers hope to use these observations to further study the distribution of dark matter and discover distant objects using gravitational lenses.
A menagerie of interesting astronomical finds fills this image from the NASA/ESA Hubble Space Telescope. As well as several large elliptical galaxies, a ring-shaped galaxy is lurking on the right of this image. A pair of bright stars are also visible at the left of this image, notable for their colorful crisscrossing diffraction spikes. This collection of astronomical curiosities is the galaxy cluster ACO S520 in the constellation Pictor, which was captured by Hubble’s Advanced Camera for Surveys.
This is one of a series of Hubble observations searching for massive, luminous galaxy clusters that had not been captured by earlier surveys. Appropriately, the proposal for observing time was named “They almost got away”! Astronomers took advantage of occasional gaps in Hubble’s busy schedule to capture images of these barely-explored galaxy clusters, revealing a wealth of interesting targets for further study with Hubble and the NASA/ESA/CSA James Webb Space Telescope.
Galaxy clusters are among the largest known objects in the Universe, and studying these objects can provide insights into the distribution of dark matter, which is responsible for most of the mass of a galaxy cluster. The vast masses of galaxy clusters are what cause many of them to act as gravitational lenses which distort and magnify light from even more distant objects. This can allow astronomers to use galaxy clusters as a kind of natural gravitational telescope to reveal distant objects that would usually be too faint to resolve — even for the crystal-clear vision of Hubble.