Figure 23-28: The M81 Group (a) The starburst galaxy M82 is part of a cluster of about a dozen galaxies. This wide-angle visible-light photograph shows the three brightest galaxies of the cluster. The area shown is about 1° across. (b) This false-color radio image of the same region, created from data taken by the Very Large Array, shows streamers of hydrogen gas that connect the three bright galaxies as well as several dim ones.

(a: Palomar Sky Survey; b: Image courtesy of NRAO/AUI)