UGC 813 and UGC 816

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About this Image

This composite image shows visible light (green), neutral Hydrogen gas (blue), and 1.4 GHz radio continuum (red) emission. The bright galaxies UGC 813 (center) and UGC 816 (left) appear white because they emit at all three wavelengths. They were normal disk galaxies that collided face-on at a speed of about 500 km/sec around 50 million years ago. Their disks have already passed through each other and are now separating. The galaxies are connected by a bridge containing magnetic fields and relativistic electrons which were stripped from their disks and still produce radio continuum emission (red). This "cosmic crash test" tells us about the collision itself and about normal galaxies via their response to such a collision.

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

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Technical Data

    Telescope VLA 
    Date of Observation 2001-07-27 
    Type of Observation Spectral Line Observations 
    Wavelength 21 cm 
    Species HI 
    Center of Image RA: 01:16:16.54, Dec: 46:44:24.20 (J2000)  
    Field of View 0.0667 x 0.1000 degrees  
    Technical Caption  

  • Astronomical database entries for UGC813
    • Query NED for images of UGC813
    • Query SIMBAD for more UGC813 data


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