Abstract
We suggest a new approach to the description of galactic structures. This approach is based on the hypothesis that these may be treated as low-frequency (slow) modes in a stellar disk that consists of orbits precessing with different angular velocities. The definition of the modes is mathematically formulated as an eigenvalue problem for the Fredholm integral operator. Two types of modes (barlike and spiral) are shown to exist. When the resonance interaction is disregarded, the bar modes are neutral disk perturbations. Their growth is attributable to the influence of the long-range gravitational field of the modes on the stars in the region of corotation and outer Lindblad resonance. The spiral perturbations are waves with a zero total angular momentum. Their growth may be due to the inner Lindblad resonance. We demonstrate the efficiency of our approximation by comparison with N-body simulations.
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Translated from Pis’ma v Astronomicheski\(\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\smile}$}}{l} \) Zhurnal, Vol. 30, No. 8, 2004, pp. 568–573.
Original Russian Text Copyright © 2004 by Polyachenko.
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Polyachenko, E.V. Galactic bars and spirals as slow modes of stellar disks. Astron. Lett. 30, 514–518 (2004). https://doi.org/10.1134/1.1784492
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DOI: https://doi.org/10.1134/1.1784492