Counterrotating Bars

Counter-rotating bars within bars

The dynamical stability and evolution of disc galaxies with different disc thickness as well as various fraction and concentration of stellar counter-rotation is investigated with self-consistent numerical simulations. In particular, systems of nested, counter-rotating, stable bars are presented. As for the direct case, the nuclear secondary bar rotates faster than the primary bar. Contrary to ...

Counterrotating galaxies formed by cosmological collapses

We investigate numerically the possibility that dissipationless cosmological collapses can lead to the formation of counterrotating galaxies. We consider systems formed from initially small density excesses embedded in the environment of other density perturbations in an otherwise homogeneous and isotropic expanding early Universe. We find that a central bar-like density excess, that can make b...

Hydrodynamic Simulations of Counterrotating Accretion Disks

Time-dependent, axisymmetric hydrodynamic simulations have been used to study accretion disks consisting of counterrotating components with an intervening shear layer(s). Configurations of this type can arise from the accretion of newly supplied counterrotating matter onto an existing corotating disk. The grid-dependent numerical viscosity of our hydro code is used to simulate the influence of ...

Counterrotating Nuclear Disks in Arp 220

The ultraluminous infrared galaxy Arp 220 has been observed at resolution in CO (2È1) and 1 mm 0A.5 continuum using the newly expanded Owens Valley Millimeter Array. The CO and continuum peaks at the double nuclei and the surrounding molecular gas disk are clearly resolved. We Ðnd steep velocity gradients across each nucleus (*V D 500 km s~1 within whose directions are not aligned with r \ 0A.3...

Bars Notices