Morphological classification of galaxies
Document Type
Encyclopedia
Role
Contributor
Publication
Encyclopedia of Astrophysics
Publisher
Elsevier
Standard Number
9780443214400
First Page
153
Last Page
168
Publication Date
8-28-2025
Abstract
The morphological classification of galaxies provides vital physical information about the orbital motions of stars in galaxies, and correlates in interesting ways with star formation history, and other physical properties. Galaxy morphological classification is a field with a history of more than 100 years of development, and many scientists have introduced new classification schemes, resulting in a sometimes confusing array of terminologies and overlapping classes. In this article I provide a brief historical review of galaxy classification, but focus mostly on providing a summary of how the morphological variety of galaxies seen in our expanding Universe are described. I review traditional visual classification, morphometric measurements, crowd-sourcing for large scale visual classifications (Galaxy Zoo), and of course the recent explosion of interest in making use of machine learning techniques for galaxy morphology classification. A look up table is provided for cross matching of various terminologies currently in use for galaxy morphology classification as well as brief definitions of the main morphological types.
Repository Citation
Masters, K. L. (2026). Morphological classification of galaxies. In Encyclopedia of Astrophysics, pp. 153–168. Elsevier. https://doi.org/10.1016/B978-0-443-21439-4.00068-7
