||Gas Dynamics in Central Regions of Barred Galaxies: Hydrodynamic Models
||459, 6th International Conference of Numerical Modeling of Space Plasma Flows (ASTRONUM 2011)
||Kim, W.-T.; Seo, W.-Y.
||We investigate dynamical evolution of gas in barred galaxies using
two-dimensional high-resolution hydrodynamic simulations.
The gaseous medium is assumed to be infinitesimally-thin,
isothermal, unmagnetized, and non-self-gravitating.
To study the effects of various galactic environments
on the gas evolution, we vary
the gas sound speed cs as well as the mass MBH of a super massive
black hole (BH) located at the galaxy center.
An introduction of the bar potential produces bar substructure including
a pair of dust-lane shocks, a nuclear ring, and nuclear spirals.
As the sound speed increases, the dust-lane shocks tend to
move closer to the bar major axis, resulting in a smaller nuclear ring.
The location of a nuclear ring is independent of the BH mass, suggesting
that the ring position is not determined by the Lindblad resonances.
Coherent nuclear spirals that develop inside a nuclear ring
can persist only when either cs is low or MBH is large:
they would otherwise be destroyed by the ring material in eccentric orbits.
While the mass
inflow rate toward the galaxy center in models with low sound speed
is quite small because of the presence of a narrow nuclear ring,
it becomes larger than 0.01Surf when cs is large, potentially
powering active galactic nuclei in Seyfert galaxies.