This system consists of a pair of galaxies, dubbed NGC 3690 (or Arp 299), which made a close pass some 700 million years ago. As a result of this interaction, the system underwent a fierce burst of star formation. In the last fifteen years or so six supernovae have popped off in the outer reaches of the galaxy, making this system a distinguished supernova factory. Arp 299 belongs to the family of ultra-luminous infrared galaxies and is located in the constellation of Ursa Major, the Great Bear, approximately 150 million light-years away. It is the 299th galaxy in Arp's Atlas of Peculiar Galaxies. Despite its enormous amount of absorbing dust, enough violet and near-ultraviolet light leaks out for it to be number 171 in B.E. Markarian's catalog of galaxies with excess ultraviolet emission.
This image is part of a large collection of 59 images of merging galaxies taken by the Hubble Space Telescope and released on the occasion of its 18th anniversary on 24th April 2008.