Gas response in chaotic bars

Abstract

We report the presence of typical straight 'dust lane shocks' in the gas response of a barred galaxy model, that lacks, to a large extent, in its stellar component the backbone of stable x1 periodic orbits. The stellar response of this model is characterized by an ansae-type bar, supported mainly by chaotic orbits. We follow the gas response by means of the smoothed particle hydrodynamics (SPH) method. The shocks along almost straight line segments inside the bar region,are formed as a result of a flow according to which gas is streaming from both sides of the 'dust lanes'. The gas then flows towards the galactic centre along them. Our simulations describe an alternative flow pattern (to the one based on elliptical motion of the gas around the centre of the galaxy) that could explain the frequently observed dust lanes in the bars of barred galaxies. © 2010 The Authors. Journal compilation © 2010 RAS.