HII Region Oxygen Abundances in Starbursting Transition Dwarf Galaxies
Abstract
We present empirical HII region oxygen abundances for a sample of low-luminosity starburst galaxies which are in a short lived evolutionary state. All five galaxies are characterized by centrally concentrated star formation, which is embedded in smooth stellar envelopes resembling dE-like systems. The galaxies also have small gas contents with typical M_{HI}/L_{B} ~ 0.1 resulting in gas exhaustion timescales less than 1 Gyr, even when molecular gas is considered. We find, compared to other morphologically similar systems, the galaxies of this sample have surprisingly high oxygen abundances with 12 + log(O/H) ~ 9.0. We propose that these objects are a subclass of evolved blue compact dwarfs, which have exhausted most of their gas supply while retaining their metals. We further propose that we are seeing these objects during a short phase in which they are nearing the end of their starburst activity, and could become early-type dwarfs.
Cite
@article{arxiv.astro-ph/0612292,
title = {HII Region Oxygen Abundances in Starbursting Transition Dwarf Galaxies},
author = {K. E. Dellenbusch and J. S. Gallagher and P. M. Knezek},
journal= {arXiv preprint arXiv:astro-ph/0612292},
year = {2011}
}
Comments
13 pages, 3 figures, accepted by ApJ Letters