NGC1300 dynamics - II. The response models

Monthly Notices of the Royal Astronomical Society (Impact Factor: 5.11). 09/2010; 408(1):9-21. DOI: 10.1111/j.1365-2966.2010.17061.x


We study the stellar response in a spectrum of potentials describing the barred spiral galaxy NGC1300. These potentials have been presented in a previous paper and correspond to three different assumptions as regards the geometry of the galaxy. For each potential we consider a wide range of Omegap pattern speed values. Our goal is to discover the geometries and the Omegap supporting specific morphological features of NGC1300. For this purpose we use the method of response models. In order to compare the images of NGC1300 with the density maps of our models, we define a new index which is a generalization of the Hausdorff distance. This index helps us to find out quantitatively which cases reproduce specific features of NGC1300 in an objective way. Furthermore, we construct alternative models following a Schwarzschild-type technique. By this method we vary the weights of the various energy levels, and thus the orbital contribution of each energy, in order to minimize the differences between the response density and that deduced from the surface density of the galaxy, under certain assumptions. We find that the models corresponding to Omegap ~ 16 and 22 kms-1kpc-1 are able to reproduce efficiently certain morphological features of NGC1300, with each one having its advantages and drawbacks. Based on observations collected at the European Southern Observatory, Chile: programme ESO 69.A-0021. E-mail: (CK); (PAP); (PG)


Available from: Constantinos Kalapotharakos
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    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.
    Monthly Notices of the Royal Astronomical Society Letters 11/2010; 409(1):L94 - L98. DOI:10.1111/j.1745-3933.2010.00955.x · 5.52 Impact Factor