Galaxy morphology, luminosity and, environment in the SDSS DR7

TL;DR

This study investigates how galaxy luminosity functions vary with environment, morphology, and color using SDSS DR7 data, revealing strong environmental effects on ellipticals but not on spirals, and highlighting the impact of dust attenuation.

Contribution

It provides a detailed analysis of the environmental dependence of galaxy luminosity functions across different morphological types and colors, using a large SDSS dataset with correction for dust absorption.

Findings

Elliptical galaxy luminosity functions strongly depend on environment.

Spiral galaxy luminosity functions are nearly environment independent.

Dust absorption affects the bright end of spiral galaxy luminosities.

Abstract

We study the influence of the environment on the evolution of galaxies by investigating the luminosity function (LF) of galaxies of different morphological types and colours at different environmental density levels. We construct the LFs separately for galaxies of different morphology (spiral and elliptical) and of different colours (red and blue) using data from the Sloan Digital Sky Survey (SDSS), correcting the luminosities for the intrinsic absorption. We use the global luminosity density field to define different environments, and analyse the environmental dependence of galaxy morphology and colour. The smoothed bootstrap method is used to calculate confidence regions of the derived luminosity functions. We find a strong environmental dependency for the LF of elliptical galaxies. The LF of spiral galaxies is almost environment independent, suggesting that spiral galaxy formation mechanisms are similar in different environments. Absorption by the intrinsic dust influences the bright-end of the LF of spiral galaxies. After attenuation correction, the brightest spiral galaxies are still about 0.5 mag less luminous than the brightest elliptical galaxies, except in the least dense environment, where spiral galaxies dominate the LF at every luminosity. Despite the extent of the SDSS survey, the influence of single rich superclusters is present in the galactic LF of the densest environment.