NGC 4618  &  NGC 4625

This particular galactic pairing known as Arp 23 finds its home in the constellation Canes Venetici. The smaller of the pair – NGC 4625 is a distorted dwarf galaxy formally classified as Sm, a structure which resembles spiral galaxies – especially the Magellanic clouds. It’s been theorized that asymmetrical structure could be the result of a gravitational interaction with NGC 4618 – its larger, interactive member in this picture. Unlike most spiral galaxies, NGC 4625 has a single spiral arm, which gives the galaxy an asymmetric appearance. It has been hypothesized that this galaxy's asymmetric structure may be the result of a gravitational interaction with NGC 4618. Such asymmetric structure is commonly seen among many interacting galaxies. However, observations of neutral hydrogen gas in NGC 4618 and NGC 4625 show that NGC 4625 does not appear to have been affected by the gravitational interaction. This indicates that the single-arm structure seen in NGC 4625 may be created through intrinsic processes.