Instability of counter-rotating stellar disks

26th IUPAP Conference on Computational Physics

物理学;计算机科学

Hohlfeld, R.G.^1,2 ; Lovelace, R.V.E.^3

Center for Computational Science, Boston University, Boston

MA

02215, United States^1

Wavelet Technologies, Inc., Attleboro

MA

02703, United States^2

Astronomy Department, Cornell University, Ithaca

NY, United States^3

关键词: Azimuthal mode number;    Boundary regions;    Density distributions;    Density fluctuation;    Initial conditions;    N-body simulation;    Spiral-density waves;    Two stream instability;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/640/1/012059/pdf
DOI  :  10.1088/1742-6596/640/1/012059

学科分类：计算机科学（综合）

来源: IOP

【 摘 要 】

We use an N-body simulation, constructed using GADGET-2, to investigate an accretion flow onto an astrophysical disk that is in the opposite sense to the disk's rotation. In order to separate dynamics intrinsic to the counter-rotating flow from the impact of the flow onto the disk, we consider an initial condition in which the counter-rotating flow is in an annular region immediately exterior the main portion of the astrophysical disk. Such counter-rotating flows are seen in systems such as NGC 4826 (known as the "Evil Eye Galaxy"). Interaction between the rotating and counter-rotating components is due to two-stream instability in the boundary region. A multi-armed spiral density wave is excited in the astrophysical disk and a density distribution with high azimuthal mode number is excited in the counter-rotating flow. Density fluctuations in the counter-rotating flow aggregate into larger clumps and some of the material in the counter-rotating flow is scattered to large radii. Accretion flow processes such as this are increasingly seen to be of importance in the evolution of multi-component galactic disks.