GALAXY COLLISIONS DOMINATE THE LOCAL UNIVERSE

Press release

Image:
(click here for a larger version and here for a full resolution 11 MB tiff file):



Explanation: The panels show several of the newly found galaxy collisions in the nearby universe, using the NOAO Deep Wide-Field Survey (NDWFS) and the Multiwavelength Survey by Yale/Chile (MUSYC). The collisions are seen in different stages of the merger process, which taken together show the sequence that occurs. In (a) and (b) [top left and top right], the galaxies are still separated, but huge tidal forces of gravity are already at work pulling stars from the galaxies into enormous broad fans that stretch hundreds of thousands of light-years in space. In (c) and (d) [bottom left and bottom right], the colliding galaxies have merged into single, larger galaxies. The violent past of these galaxies can be inferred from the tidal "debris" that still surrounds the newly formed galaxies.

Individual eps and fits files

Movie:


MPEG (3.1 MB)
AVI (7.0 MB)
QuickTime (7.0 MB)
Movie by M. Steinmetz

Explanation: The movie shows a computer simulation of the formation of a large galaxy. Time is compressed in the simulation: the entire history of the universe (13.7 billion years) spans about 20 seconds. Computer simulations like these have predicted that all galaxies grow by collisions, and subsequent mergers, of smaller galaxies. The new observations demonstrate, for the first time, that these collisions are indeed very common in the local universe.

Citation:

Astronomical Journal 130, page 2647-2665 (December 2005).
PDF version

Credits:

Based in Tucson, AZ, the National Optical Astronomy Observatory (NOAO) consists of Kitt Peak National Observatory near Tucson, AZ, Cerro Tololo Inter-American Observatory near La Serena, Chile, and the NOAO Gemini Science Center. NOAO is operated by the Association of Universities for Research in Astronomy (AURA) Inc., under a cooperative agreement with the National Science Foundation. The movie was made by M. Steinmetz at the Astrophysical Institute of Potsdam, and was published in New Astronomy 7, page 155 (2002).