Luminosity-Metallicity Relations for Blue Compact Dwarf Galaxies in the Optical and Near-Infrared

TL;DR

This study systematically examines the luminosity-metallicity relations in blue compact dwarf galaxies across optical and near-infrared bands, confirming the relation's validity and exploring factors influencing its scatter.

Contribution

It reconciles previous contradictory findings and demonstrates that the L-Z relation holds for blue compact dwarf galaxies across multiple bands, with insights into factors affecting its scatter.

Findings

L-Z relation exists for blue compact dwarf galaxies in optical and near-infrared.

The slope of the L-Z relation is shallower in near-infrared bands.

Star formation activity and internal absorption influence the scatter in the L-Z relation.

Abstract

In this paper, we present systematic studies on the B-, R- and $K_s$-band luminosity-metallicity (L-Z) relations for a set of metal poor, blue compact dwarf galaxies. Metallicity is derived by using both the empirical N2 and the direct $T_e$ methods. Our work reconciles contradictory results obtained by different authors and shows that the L-Z relationship does also hold for blue compact dwarf galaxies. The empirical N2-based slope of the L-Z relation, for each photometric band, is consistent with the $T_e$-based one. We confirm that the slope of the L-Z relation is shallower in the near-infrared than that in the optical. Our investigations on the correlations between the $L_B$-Z relation residuals and different galactic parameters show that the star formation activities could be a cause of the large scatter in the optical L-Z relationships, whereas the internal-absorption might be another possible contributing factor.