image: Arp 148 shows the aftermath of an encounter between two galaxies, resulting in a ring-shaped galaxy and a long-tailed companion. The collision between the two parent galaxies produced a shockwave effect that first drew matter into the center and then caused it to propagate outwards in a ring. The elongated galaxy perpendicular to the ring suggests that Arp 148 is a unique snapshot of an ongoing collision. Infrared observations reveal an obscured region that appears as a dark dust lane across the nucleus in optical light. Arp 148 is nicknamed "Mayall’s object" and is located in the constellation of Ursa Major, the Great Bear, approximately 500 million light-years away. This interacting pair of galaxies is included in Arp's catalogue of peculiar galaxies as number 148. 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 April 24, 2008. view more
Credit: NASA/ ESA/ STScI/AURA (The Hubble Heritage Team) - ESA/Hubble Collaboration/ University of Virginia, Charlottesville, NRAO, Stony Brook University (A. Evans)/ STScI (K. Noll)/ Caltech (J. Westphal)
Galaxy collisions produce a remarkable variety of intricate structures, as 59 new images from the NASA/ESA Hubble space telescope show.
Interacting galaxies are found throughout the Universe, sometimes dramatic collisions that trigger bursts of star formation, on other occasions as stealthy mergers that form new galaxies.
A series of 59 new images of colliding galaxies, the largest collection ever published simultaneously, has been released from archived raw Hubble images to mark the 18th anniversary of the telescope’s launch.
Galaxy mergers, which were more common in the early Universe than they are today, are thought to be one of the main driving forces for cosmic evolution, turning on quasars, sparking frenetic star births and explosive stellar deaths.
Even apparently isolated galaxies will show signs in their internal structure that they have experienced one or more mergers in their past. Each of the various merging galaxies in this series of images is a snapshot of a different instant in the long interaction process.
For the entire collection of 59 images, please see this article on the European Hubble homepage at: http://www.spacetelescope.org/news/html/heic0810.html