Supercomputer Simulations Pin Down Galaxy Collision Rates

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From the University of California, Santa Cruz comes this story about how a new analysis of images from the Hubble Space Telescope combined with supercomputer simulations of galaxy collisions has cleared up years of confusion about the rate at which smaller galaxies merge to form bigger ones.

In the new work, all the previous observations were reanalyzed using a key new ingredient: highly accurate computer simulations of galaxy collisions. These simulations, which include the effects of stellar evolution and dust, show the lengths of time over which close galaxy pairs and various types of galaxy disturbances are likely to be visible. Lotz’s team accounted for a broad range of merger possibilities, from a pair of galaxies with equal masses joining together to an interaction between a giant galaxy and a puny one. The team also analyzed the effects of different orbits for the galaxies, possible collision impacts, and how the galaxies were oriented to each other.

The paper on this work, entitled “The Major and Minor Galaxy Merger Rates at z < 1.5,” has been accepted for publication in the Astrophysical Journal. Read the Full Story.