Morphological Distribution of Galaxies in Some Nearby Clusters

Khalid K Mohammad,Mariwan A Rasheed

doi:10.1515/astro-2019-0007

Abstract

Abstract We study the morphological distribution of galaxies in some nearby clusters, using the Sloan Digital Sky Survey – Data Release 9 (SDSS-DR9). The segregation between early-type galaxies and late-type ones is investigated in g – r / u – g color space, using the color cut u – r = 2.22. The results are compared with those obtained using a color cut that changes with magnitude. They are found to be consistent, particularly for late-type galaxies. The results obtained by the fixed color-cut criterion are also found to be consistent with those obtained by the inverse concentration index parameter, especially for early-type galaxies. Comparable results are obtained for the stacked sample, whose morphologies, given by the fixed color-cut criterion are compared with the visual morphologies provided by the Galaxy Zoo project. A good degree of consistency is seen, which becomes more evident for late-type galaxies.

Highlights

Galaxy morphology has received a considerable interest since a long time, due to its important role in the study of galaxy formation and evolution. De Vaucouleurs (1961) found that morphology of galaxies correlates with their colors
We study the morphological distribution of galaxies in some nearby clusters, using the Sloan Digital Sky Survey – Data Release 9 (SDSS-DR9)
Comparable results are obtained for the stacked sample, whose morphologies, given by the fixed color-cut criterion are compared with the visual morphologies provided by the Galaxy Zoo project

Summary

Introduction

Galaxy morphology has received a considerable interest since a long time, due to its important role in the study of galaxy formation and evolution. De Vaucouleurs (1961) found that morphology of galaxies correlates with their colors. With the aid of the Sloan Digital Sky Survey (SDSS, York et al 2000) and the Galaxy Zoo project (Lintott et al 2008), it was found that a certain population of blue early-type galaxies do not reside on the red sequence (Schawinski et al 2009). These blue early-type galaxies help us understand the physical processes underlying their evolution, and give evidence for star formation activity in various morphological types

Objectives

Results

Conclusion