Surface brightness profiles of blue compact dwarf galaxies in the GOODS-N and GOODS-S field

TL;DR

This study analyzes the structural properties of 34 blue compact dwarf galaxies using deep optical and near-infrared imaging, revealing similarities with dwarf ellipticals and suggesting a possible evolutionary link.

Contribution

It provides the deepest NIR surface brightness profiles of BCDs and compares their structural parameters with other dwarf galaxies, proposing a unified evolutionary scenario.

Findings

BCD hosts are smaller than early-type dwarfs at fixed luminosity in B band.

Structural parameters of BCDs and dEs are more similar in H band.

All dwarf galaxies follow a common luminosity-radius relation.

Abstract

We investigate the structural properties of the underlying hosts of 34 blue compact dwarf (BCD) galaxies with deep near-infrared (NIR) photometry. The BCD sample is selected from the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey in the Great observatories origins Deep Survey North and South fields. We extract the surface brightness profile (SBP) in the optical F 435W and NIR F 160W bands. The SBPs of BCDs in the H band reach 26 mag arcsec^-2 at the 3\sigma level, which is so far the deepest NIR imaging of BCDs. Then we fit the SBPs with one- and two- component Sersic models. About half of the BCDs favour the two-component model which significantly improves the fit quality. The effective radii of the underlying hosts of BCDs in the B band are smaller than those of early-type dwarfs (dEs) and dwarf irregulars at a fixed luminosity. This discrepancy is similar to findings in many previous works. However, the difference in structural parameters between BCDs and other dwarf galaxies seems to be less significant in the H band. Furthermore, we find a remarkable agreement between the underlying hosts of BCDs and dEs. All dwarf galaxies seem to follow a similar luminosity-radius relationship which suggests a unified structural evolution for dwarf galaxies. We conclude that a possible evolution track from BCDs to dEs cannot be ruled out, with no significant change of structure needed in the evolutionary scenario.