A kinematic study of the neutral and ionised gas in the irregular dwarf galaxies IC 4662 and NGC5408?

The feedback between massive stars and the interstellar medium is one of the most important processes in the evolution of dwarf galaxies. This interaction results in nu-merous neutral and ionised gas structures that have been found both in the disc and in the halo of these galaxies. However, their origin and fate are still poorly understood. We here present new H i and optical data of two Magellanic irregular dwarf galaxies in the Local Volume: IC 4662 and NGC 5408. The H i line data were obtained with the Australia Telescope Compact Array and are part of the “Local Volume H i Survey”. They are complemented by optical images and spectroscopic data obtained with the ESO New Technology Telescope and the ESO 3.6m telescope. Our main aim is to study the kinematics of the neutral and ionised gas components in order to search for outflowing gas structures and to make predictions about their fate. Therefore, we perform a Gaussian decomposition of the H i and Hα line profiles. We find the H i gas envelopes of IC 4662 and NGC 5408 to extend well beyond the op-tical discs, with H i to optical diameter ratios above four. The optical disc is embedde