Two of the galaxies in the galactic triplet Arp 248 — also known as Wild’s Triplet — are seen in this image from the NASA/ESA Hubble Space Telescope. Arp 248 is located approximately 200 million light-years from Earth in the constellation Virgo. The two large spiral galaxies visible in this image — which flank a smaller, unrelated background spiral galaxy — appear to be connected by a luminous bridge. Known as a tidal tail, this elongated stream of stars and interstellar dust was formed by the mutual gravitational attraction of the two foreground galaxies.
This observation comes from a project which delves into two rogues’ galleries of weird and wonderful galaxies: A Catalogue of Southern Peculiar Galaxies and Associations, compiled by astronomers Halton Arp and Barry Madore, and the Atlas of Peculiar Galaxies, compiled by Halton Arp. Each collection contains a menagerie of spectacularly peculiar galaxies, including interacting galaxies such as Arp 248, as well as one- or three-armed spiral galaxies, galaxies with shell-like structures, and a variety of other space oddities.
Hubble used its Advanced Camera for Surveys (ACS) to scour this menagerie of eccentric galaxies in search of promising candidates for future observations with the NASA/ESA/CSA James Webb Space Telescope, the Atacama Large Millimeter/submillimeter Array, and Hubble itself. With such a wealth of astronomical objects to study in the night sky, projects such as this, which guide future observations, are a valuable investment of observing time. As well as the scientific merits of observing these weird and wonderful galaxies, they were also — very unusually — selected as Hubble targets because of their visual appeal to the general public!