Using GAMA and H-ATLAS Data to Explore the Cold Dust Properties of Early-Type Galaxies

TL;DR

This study investigates the cold dust properties of early-type galaxies using GAMA and Herschel-ATLAS data, aiming to understand their origins and relation to galaxy features.

Contribution

It introduces selection criteria for early-type galaxies and analyzes their dust characteristics through multi-wavelength data and modified Planck function fitting.

Findings

A robust selection method for ETGs using optical and morphological criteria

Initial estimates of dust temperatures and masses in ETGs

Correlation between dust properties and galaxy morphology

Abstract

Hierarchical galaxy formation models predict the development of elliptical galaxies through a combination of the mergers and interactions of smaller galaxies. We are carrying out a study of Early-Type Galaxies (ETGs) using GAMA multi-wavelength and Herschel-ATLAS sub- mm data to understand their intrinsic dust properties. The dust in some ETGs may be a relic of past interactions and mergers of galaxies, or may be produced within the galaxies themselves. With this large dataset we will probe the properties of the dust and its relation to host galaxy properties. This paper presents our criteria for selecting ETGs and explores the usefulness of proxies for their morphology, including optical colour, Sersic index and Concentration index. We find that a combination of criteria including r band Concentration index, ellipticity and apparent sizes is needed to select a robust sample. Optical and sub-mm parameter diagnostics are examined for the selected ETG sample, and the sub-mm data are fitted with modified Planck functions giving initial estimates for the cold dust temperatures and masses.