Bibcode
Łokas, E. L.; Athanassoula, E.; Debattista, V. P.; Valluri, M.; del Pino, A.; Semczuk, M.; Gajda, G.; Kowalczyk, K.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 445, Issue 2, p.1339-1350
Fecha de publicación:
12
2014
Número de citas
67
Número de citas referidas
62
Descripción
Using N-body simulations, we study the properties of a bar induced in a
discy dwarf galaxy as a result of tidal interaction with the Milky Way.
The bar forms at the first pericentre passage and survives until the end
of the evolution at 10 Gyr. Fourier decomposition of the bar reveals
that only even modes are significant and preserve a hierarchy so that
the bar mode is always the strongest. They show a characteristic profile
with a maximum, similar to simulated bars forming in isolated galaxies
and observed bars in real galaxies. We adopt the maximum of the bar mode
as a measure of the bar strength and we estimate the bar length by
comparing the density profiles along the bar and perpendicular to it.
The bar strength and the bar length decrease with time, mainly at
pericentres, as a result of tidal torques acting at those times and not
to secular evolution. The pattern speed of the bar varies significantly
on a time-scale of 1 Gyr and is controlled by the orientation of the
tidal torque from the Milky Way. The bar is never tidally locked, but we
discover a hint of a 5/2 orbital resonance between the third and fourth
pericentre passage. The speed of the bar decreases in the long run so
that the bar changes from initially rather fast to slow in the later
stages. The boxy/peanut shape is present for some time and its
occurrence is preceded by a short period of buckling instability.
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