Tidal Interactions in M81 Group

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About this Image

This pair of images illustrates the need to study celestial objects at different wavelengths in order to get "the whole picture" of what is happening with those objects. At left, you see a visible-light image of the M81 Group of galaxies (from the Digital Sky Survey), shown in a reversed greyscale (dark regions are brighter). Most of the light in this image comes from stars in the galaxies. At right, a radio image, made with the VLA, shows the hydrogen gas, including streamers of gas connecting the galaxies. From the radio image, it becomes apparent that this is an interacting group of galaxies, not isolated objects.

Investigator(s):  Min S. Yun, Paul T.P. Ho, K.Y. Lo

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Technical Data

    Telescope VLA 
    Type of Observation Spectral Line Observations 
    Wavelength 21 cm 
    Frequency 1420.4 MHz 
    Species HI 
    Center of Image RA: 09:55:33.17, Dec: 69:03:55.10  
    Field of View 2.0000 x 2.0000 degrees  
    Technical Caption The HI observations consist of a 12-pointing mosaic with the VLA in its most compact D-array configuration.  

  • Astronomical database entries for M81 group
    • Query NED for images of M81 group
    • Query SIMBAD for more M81 group data


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