Bars and spirals in tidal interactions with an ensemble of galaxy mass models
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We present simulations of the gaseous and stellar material in several
different galaxy mass models under the influence of different tidal fly-bys to
assess the changes in their bar and spiral morphology. Five different mass
models are chosen to represent the variety of rotation curves seen in nature.
We find a multitude of different spiral and bar structures can be created, with
their properties dependent on the strength of the interaction. We calculate
pattern speeds, spiral wind-up rates, bar lengths, and angular momentum
exchange to quantify the changes in disc morphology in each scenario. The
wind-up rates of the tidal spirals follow the 2:1 resonance very closely for
the flat and dark matter dominated rotation curves, whereas the more baryon
dominated curves tend to wind-up faster, influenced by their inner bars. Clear
spurs are seen in most of the tidal spirals, most noticeable in the flat
rotation curve models. Bars formed both in isolation and interactions agree
well with those seen in real galaxies, with a mixture of "fast" and "slow"
rotators. We find no strong correlation between bar length or pattern speed and
the interaction strength. Bar formation is, however, accelerated/induced in
four out of five of our models. We close by briefly comparing the morphology of
our models to real galaxies, easily finding analogues for nearly all
simulations presenter here, showing passages of small companions can easily
reproduce an ensemble of observed morphologies.
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