A Study on the Chemical Properties of Blue Compact Dwarf Galaxies

TL;DR

This study analyzes the chemical and gaseous properties of 53 blue compact dwarf galaxies, revealing differences between types and suggesting varied evolutionary paths influenced by gas flows and mergers.

Contribution

It provides the first detailed correlation analysis of chemical properties across a large sample of BCDs, highlighting differences between E- and I-type galaxies.

Findings

E-type BCDs are more gas-poor and metal-rich than I-type at similar baryonic masses.

Correlations suggest BCDs have experienced gas flows or mergers, not isolated evolution.

Different types of BCDs may be at distinct evolutionary stages or have different progenitors.

Abstract

In this paper, we report our studies on the gaseous and chemical properties of a relatively large sample (53 members) of blue compact dwarf galaxies (BCDs). The results of correlations among the oxygen abundance, stellar mass, gas mass, baryonic mass, and gas fraction are present both for E- and I-type BCDs, which are classified according to Loose & Thuan (1985) and show elliptical and irregular outer haloes, respectively. These correlations of I-type BCDs show similar slopes to those of E-type ones. However, in general, E-type BCDs are more gas-poor and metal-rich than I-type ones at a given baryonic mass. Based on these results, we suggest that E-type BCDs, at least a part of them, and I-type ones might be likely at different evolutionary phases and/or having different progenitors. Our investigation of the correlation between oxygen abundance and gas fraction shows that BCDs appear to have not evolved as isolated systems, but to have experienced some gas flows and/or mergers.