The fate of the gas in nearby irregular dwarf galaxies
J. van Eymeren

The low metal content of dwarf galaxies and the metal enrichment of the
intergalactic medium both suggest that mass loss from galaxies is a
significant factor for their chemical evolution history. However, no clear
evidence of a blow-away in local dwarf galaxies has been found so far.
Therefore, we performed a detailed kinematic study of the neutral and ionised
gas components in a sample of four fairly isolated nearby irregular dwarf
galaxies. We searched for expanding gas structures and compared their
velocities to the escape velocity of their host galaxy in order to get an
idea whether the gas can leave the gravitational potential by becoming a
freely flowing wind or whether it is still gravitationally bound. The escape
velocity was estimated using the pseudo-isothermal halo model. We detected
expanding gas structures with velocities between 20 and 110 km/s in all
sample galaxies, but they are all gravitationally bound.