Some Musings on Galaxy Morphology

Abstract

Careful inspection of large-scale photographs of Shapley-Ames galaxies seems to show a smooth transition between the morphological characteristics of galaxies located on the narrow red, and on the broad blue, sequences in the galaxian color-magnitude diagram. In other words there does not appear to be a dichotomy between blue and red galaxies. Both the colors and the morphologies of galaxies are found to correlate strongly with their environments. Red and early-type Shapley-Ames galaxies are dominant in clusters, whereas blue late-type star forming objects dominate the general field. Interestingly the colors and morphologies of galaxies in small groups resemble the field and differ from those in clusters. As noted by Baade the presence of dust and star formation are very closely correlated, except in a few galaxies that probably had unusual evolutionary histories. Over the entire range from S0 to Sc there is no significant difference between the integrated colors of normal and barred objects suggesting that the formation of a bar does not significantly affect the stellar evolutionary history of a galaxy.

13 figures; Astronomical Journal in press

References in corpus (13)

• Quantifying the bimodal color-magnitude distribution of galaxies
• Galaxy Luminosity Functions to z~1: DEEP2 vs. COMBO-17 and Implications for Red Galaxy Formation
• Galaxy bimodality versus stellar mass and environment
• Modelling the Galaxy Bimodality: Shutdown Above a Critical Halo Mass
• The dependence on environment of the color-magnitude relation of galaxies
• Stellar Population Diagnostics of Elliptical Galaxy Formation
• Environmental Dependence of Properties of Galaxies in the Sloan Digital Sky Survey
• The Millennium Galaxy Catalogue: morphological classification and bimodality in the colour-concentration plane
• Internal and Collective Properties of Galaxies in the Sloan Digital Sky Survey
• The Fundamental Properties of Galaxies and a New Galaxy Classification System
• The cross-correlation between galaxies of different luminosities and Colors
• An Observational Limit on the Dwarf Galaxy Population of the Local Group
• The Color Magnitude Distribution of Field Galaxies to z~3: the evolution and modeling of the blue sequence

Cited by in corpus (14)

• The Atlas3D project -- I. A volume-limited sample of 260 nearby early-type galaxies: science goals and selection criteria
• Galaxy Zoo: the dependence of morphology and colour on environment
• Structure and Kinematics of Early-Type Galaxies from Integral-Field Spectroscopy
• The shape of oxygen abundance profiles explored with MUSE: evidence for widespread deviations from single gradients
• Combined Effects of Galaxy Interactions and Large-Scale Environment on Galaxy Properties
• Galaxy Colour, Morphology, and Environment in the Sloan Digital Sky Survey
• The ATLAS3D Project - XXI. Correlations between gradients of local escape velocity and stellar populations in early-type galaxies
• The Millennium Galaxy Catalogue: Exploring the Color-Concentration Bimodality via Bulge-Disc Decomposition
• Frequency and properties of bars in cluster and field galaxies at intermediate redshifts
• The zCOSMOS redshift survey: the three-dimensional classification cube and bimodality in galaxy physical properties
• The migration of nearby spirals from the blue to red sequence: AGN feedback or environmental effects?
• Galaxy and Mass Assembly (GAMA): Dust obscuration in galaxies and their recent star formation histories
• Aging of galaxies along the morphological sequence, marked by bulge growth and disk quenching
• The Magnitude-Diameter Relation of Galaxies