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

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