2001/03/31 by Clayton Heller, Isaac Shlosman, P. Englmaier +1 · 3 citations
Physics and Astronomy · #Astrophysics #Astrophysics and Star Formation Studies #Bar (unit) #Classical mechanics #Decoupling (probability) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gravitation #Gravitational field #Gravitational potential #Inflow #Instability #Mechanics #Physics #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/320983
10 pages, Latex plus 8 figures, ApJ double column macros, mpeg simulations available from the on-line edition of the Astrophysical Journal, or from authors. to be published in Astrophysical Journal, Vol. 551, April 20, 2001
arxiv created 2001/03/31 · openalex publication_date 2001/06/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We find that nuclear rings in barred galaxies can be subject to a new type of non-self-gravitational dynamical instability. The instability leads to the formation of gaseous molecular bars with pattern speeds that are substantially slower than speeds of the primary stellar bars. This spectacular decoupling of nuclear bars from the underlying gravitational potential is triggered but is not driven by the gas viscosity. We find that low-viscosity systems can spend a substantial period of time in a fully decoupled state, with the nuclear bar slowly tumbling in the gravitational field of the primary bar. Higher viscosity systems form nuclear bars that librate about the primary bar. The shape of a nuclear bar, i.e., its eccentricity, correlates strongly with the angle between the bars. We also find that such decoupling, partial or full, most probably will be associated with bursts of star formation and with gas inflow across the inner (Lindblad) resonance zone toward smaller radii.