Diffuse ionized gas in the dwarf galaxy DDO 53

Abstract

We study the diffuse ionized gas (DIG) in the M81 group dwarf irregular galaxy DDO 53. We use long-slit spectroscopy in order to determine the most interesting line ratios. We compare these ratios with classical and leaking photoionization, shocks and turbulent layer models. As other dwarf irregular galaxies, the spectral characteristics are very diferent to those of the DIG in spiral galaxies: the excitation is higher and the [SII/Hα] much lower. A combination of leakage photoionization models plus shocks will be able to explain these characteristics. © 2007 Springer.