title: Bautz–Morgan classification
text: # Bautz–Morgan classification
  
  The Bautz–Morgan classification was developed in 1970 by Laura P. Bautz and William Wilson Morgan to categorize galaxy clusters based on their morphology. It defines three main types: I, II, and III. Intermediate types (I-II, II-III) are also allowed. A type IV was initially proposed, but later redacted before the final paper was published.
  
  ## Classification
  
  * A type I cluster is dominated by a bright, large, supermassive cD galaxy; for example Abell 2029 and Abell 2199.
  * A type II cluster contains elliptical galaxies whose brightness relative to the cluster is intermediate to that of type I and type III. The Coma Cluster is an example of a type II.
  * A type III cluster has no remarkable members, such as the Virgo Cluster. Type III has two subdivisions, type IIIE and type IIIS
     * Type IIIE clusters do not contain many giant spirals
     * Type IIIS clusters contain many giant spirals
  * The deprecated type IV was for clusters whose brightest members were predominantly spirals.
  
  ## Examples
  
  | Example | Type |
  | - | - |
  | Abell 2199 | Type I |
  | Abell S740 | Type I-II |
  | Coma Cluster | Type II |
  | Abell 1689 | Type II-III |
  | Virgo Cluster | Type III |
  | | Type IIIS |
  | | Type IIIE |
  