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Mass distribution and kinematics of the barred galaxies NGC 3992 and NGC 7479
K. Wilke * 1,2,
C. Möllenhoff 2 and
M. Matthias 3,4
Received 17 May 2000 / Accepted 20 July 2000
We present morphological and kinematical models for the intermediate-type barred galaxies NGC 3992 and NGC 7479. Two-dimensional models of the observed NIR surface brightness distributions with three components (bulge, bar, disk) are used for the construction of corresponding models of the stellar mass distribution. The resulting potentials are implemented numerically in a code for the computation of collisionless closed orbits for clouds. These gas clouds serve as test particles in the potential and are used for the examination of the phase space and the construction of artificial gas rotation curves. The artificial rotation curves are confronted with observed rotation curves. The model parameters of bulge, disk, and bar are adjusted by iteratively computing and evaluating a large number of different models, until an optimal fit to the observations was obtained. The effects of changing single parameter values and possible error sources are discussed. Special emphasis is put on the role of bar asymmetries in the case of NGC 7479 and the bar pattern speed in both objects.
Final models are presented which reproduce the overall morphological structure (bulge, bar, disk) of NGC 3992 and NGC 7479 as well as the rotation curves with most of their details in a consistent manner. The parameters needed for an optimal representation of the rotation curves and those derived morphologically are in very good agreement. It is shown that our modelling technique is able to explain the velocity fields of both galaxies especially in the regions dominated by the bar component.
Key words: galaxies: kinematics and dynamics galaxies: photometry galaxies: structure stars: kinematics ISM: kinematics and dynamics
Send offprint requests to: K. Wilke (firstname.lastname@example.org)
Online publication: October 2, 2000