Bautz–Morgan classification
# 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 |
