A new atlas of interacting and merging pairs of galaxies will provide astronomers insights into the connection between galaxy evolution and galaxy environment.
Scientists at the Department of Energy's Fermi National Accelerator Laboratory (Fermilab) presented this new atlas at the American Astronomical Society meeting in Albuquerque, NM, on June 4, 2002.
Astronomers Sahar Allam of the National Research Institute for Astronomy & Geophysics (NRIAG) in Egypt and Douglas Tucker of Fermilab discovered more than 10,000 previously unknown interacting and merging pairs of galaxies in data from the Sloan Digital Sky Survey Early Data Release (SDSS EDR; see http://www.sdss.org). Shown here are color images of four of these newly discovered interacting and merging pairs of galaxies. (We acknowledge the use of software written by Fermilab scientist Stephen Kent to create these color images from the SDSS EDR imaging data.)
These galaxy pairs are similar to the pair of colliding galaxies known as "The Mice" recently observed by Hubble's newest camera (PHOTO NO.: STScI-PRC02-11d), but the galaxy pairs shown here are three to five times farther away from us than are "The Mice". ("The Mice" are 300 million light years from us. The galaxy pairs shown here are between 900 million to 1.5 billion light years from us.)
These images dramatically illustrate how galaxies exchange matter when they collide. The titanic collisions have triggered star formation in these galaxies as evidenced by their blue-tinted star forming regions. Bound to each other by gravity, the galaxies in these pairs are doomed to experience future collisions with each other, eventually merging over time into a single large galaxy.