The second pair of Taffy Galaxies

Minimum credit line: Image courtesy of NRAO/AUI and J. M. Uson (NRAO)(for details, see Image Use Policy).

About this Image

The "Taffy" galaxies: This composite image shows the results of a collision between two galaxies, UGC 813 (right) and UGC 816 (left). The optical emission from stars appears in its natural color, 21 cm radio emission from interstellar atomic Hydrogen (HI) gas is shown in blue, and 1.4 GHz radio continuum emission in red. UGC 813 and UGC 816 were normal disk galaxies before they collided face-on at a speed of one million miles per hour about 50 million years ago. The disks of stars and dense clouds of molecular gas passed through each other relatively unharmed and are now separating. Diffuse HI gas clouds cannot interpenetrate and were stopped between the galaxies or thrown out in long tails by tidal forces. Disk magnetic fields are anchored by dense molecular clouds and are being stretched like bands of taffy between the galaxies as they separate. The bridge of magnetic fields and relativistic electrons stripped from the disks by the collision produces the radio continuum emission depicted in red. The wreckage from this "cosmic crash test" contains forensic evidence about both the collision itself and the nature of normal galaxies, through their response to such a collision. Investigator(s): J. J. Condon (NRAO), G. Helou (IPAC) and T. H. Jarrett (IPAC) Image Composition: J. M. Uson

Investigator(s):  J. J. Condon (NRAO), G. Helou (IPAC), T. H. Jarrett (IPAC)

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Technical Data

    Telescope VLA 
    Date of Observation 2001-07-27 
    Type of Observation Spectral Line Observations 
    Center of Image RA: 01:16:16.54, Dec: 46:44:24.20 (J2000)  
    Field of View 0.1667 x 0.1667 degrees  

  • Astronomical database entries for UGC813
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