Three mechanisms for bar thickening
Abstract
We present simulations of bar-unstable stellar discs in which the bars thicken into box/peanut shapes. Detailed analysis of the evolution of each model revealed three different mechanisms for thickening the bars. The first mechanism is the well-known buckling instability, the second is the vertical excitation of bar orbits by passage through the 2:1 vertical resonance, and the third is a gradually increasing fraction of bar orbits trapped into this resonance. Since bars in many galaxies may have formed and thickened long ago, we have examined the models for fossil evidence in the velocity distribution of stars in the bar, finding a diagnostic to discriminate between a bar that had buckled from the other two mechanisms.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 2020
- DOI:
- 10.1093/mnras/staa1336
- arXiv:
- arXiv:2005.05184
- Bibcode:
- 2020MNRAS.495.3175S
- Keywords:
-
- galaxies: bulges;
- galaxies: evolution;
- Galaxy: kinematics and dynamics;
- galaxies: kinematics and dynamics;
- galaxies: structure;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 18 pages, 17 figures, accepted to appear in MNRAS, comments welcome