Published in "Galaxies and the Universe", edited by A. Sandage, M. Sandage and J. Kristian, 1975
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CLASSIFICATION AND STELLAR CONTENT OF GALAXIES OBTAINED FROM DIRECT PHOTOGRAPHY
Allan Sandage
Hale Observatories,
Carnegie Institution of Washington
,
California Institute of Technology
Table of Contents
INTRODUCTION
EARLY CLASSIFICATION OF GALAXIES
DEVELOPMENT OF THE MODERN SYSTEM
Early Isolation of the Types
The Early Hubble System
Hubble's Major Modification Between 1936 and 1950
Finer Subdivision Along the Sequence
REVISION BY DE VAUCOULEURS
Extension of the Sequence Beyond Sc
Transition Between Ordinary and Barred Spirals
The r and s Varieties
Graphical Representation of the Classification
Additional Features of the de Vaucouleurs Revision
SELECTED ILLUSTRATIONS OF GALAXY TYPES
Elliptical Galaxies
Spirals with Thin Filamentary Arms
Spirals with Massive Arms
Transitions Between Sa and Sb
Pure Barred Galaxies
Sdm, Sm, and Im
Ir II Galaxies
Interacting Galaxies
VAN DEN BERGH'S CLASSIFICATION
MORGAN'S CLASSIFICATION BASED ON THE LUMINOSITY CONCENTRATION OF THE SPHEROIDAL COMPONENT
SYSTEM OF VORONTSOV-VELYAMINOV
COMPARISON OF THE CLASSIFICATION SYSTEMS
SEYFERT GALAXIES, N GALAXIES, AND QUASARS
STELLAR CONTENT RELATED TO TYPE: FORMATION AND EVOLUTION
REFERENCES