Atomic Hydrogen in M81

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

About this Image

The galaxy M81 is a spiral galaxy about 11 million light-years from Earth. It is about 50,000 light-years across. In the optical (not shown), the galaxy is known as a "Grand Design" spiral, for its pair of symmetric, well-defined spiral arms. This image, which only shows the cold atomic hydrogen gas in the galaxy, clearly shows that the gas also follows this grand design pattern. In this pseudocolor image, red indicates higher gas densities and blue weaker emission.

Investigator(s):  D. S. Adler, D. J. Westpfahl

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Technical Data

    Telescope VLA 
    Date of Observation 1992-08-01 
    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 0.6500 x 0.6500 degrees  
    Technical Caption The observations consist of data taken with the VLA in the B-array, C-array and D-array configurations for a total of more than 60 hours of observing time. Two pointings and two velocity settings were used. The resolution is 12". The continuum sources have not been removed from the map.  

  • Astronomical database entries for m81
    • Query NED for images of m81
    • Query SIMBAD for more m81 data


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