NGC 3628 and an example of an ultra-compact dwarf galaxy (annotated)

NGC 3628, sometimes nicknamed the Hamburger Galaxy or Sarah's Galaxy, is an unbarred spiral galaxy about 35 million light-years away in the constellation Leo. Extending to the left of NGC 3628 for around 300,000 light-years is a ‘tidal tail’ — an elongated region of stars that arises as a result of gravitational interaction with another galaxy. Embedded within this tidal tail is the ultra-compact dwarf galaxy known as NGC 3628-UCD1.

This image was captured by the US Department of Energy’s (DOE) Dark Energy Camera mounted on the National Science Foundation’s (NSF) Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile, a Program of NSF NOIRLab. NGC 3628 was not part of the survey of the Virgo Cluster.