The Secular Evolution of Disk Structural Parameters
Top Cited Papers
- 1 July 2006
- journal article
- research article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 645 (1), 209-227
- https://doi.org/10.1086/504147
Abstract
We present a comprehensive series of simulations to study the secular evolution of disk galaxies expected in a ΛCDM universe. Our simulations are organized in a hierarchy of increasing complexity, ranging from rigid-halo collisionless simulations to fully live simulations with gas and star formation. Our goal is to examine which structural properties of disk galaxies may result from secular evolution rather than from hierarchical assembly. In the vertical direction, we find that various mechanisms lead to heating, the strongest of which is the buckling instability of a bar, which leads to peanut-shaped bulges; these can be recognized face-on even in the presence of gas. We find that bars are robust structures that survive buckling and require a large (~20% of the total mass of the disk) central mass concentration to be destroyed. This can occur in dissipative simulations, where bars induce strong gas inflows, but requires that radiative cooling overcome heating. We show how angular momentum redistribution leads to increasing central densities and disk scale lengths and to profile breaks at large radii. The breaks in these simulations are in excellent agreement with observations, even when the evolution is collisionless. Disk scale lengths increase even when the total disk angular momentum is conserved; thus, mapping halo angular momenta to scale lengths is nontrivial. A decomposition of the resulting profile into a bulge+disk gives structural parameters in reasonable agreement with observations although kinematics betrays their bar nature. These findings have important implications for galaxy formation models, which have so far ignored or introduced in a very simplified way the effects of nonaxisymmetric instabilities on the morphological evolution of disk galaxies.Other Versions
This publication has 106 references indexed in Scilit:
- Bending instability of stellar disks: The stabilizing effect of a compact bulgeAstronomy Letters, 2005
- Bulgeless Galaxies and Their Angular Momentum ProblemThe Astrophysical Journal, 2004
- Mechanisms of the vertical secular heating of a stellar diskAstronomy Letters, 2003
- A Fundamental Relation between Supermassive Black Holes and Their Host GalaxiesThe Astrophysical Journal, 2000
- Dark Halo and Disk Galaxy Scaling Laws in Hierarchical UniversesThe Astrophysical Journal, 2000
- Gas-driven evolution of stellar orbits in barred galaxiesMonthly Notices of the Royal Astronomical Society, 1998
- Hubble Space TelescopeImaging of the CFRS and LDSS Redshift Surveys. II. Structural Parameters and the Evolution of Disk Galaxies toz∼ 1The Astrophysical Journal, 1998
- The formation of galactic discsMonthly Notices of the Royal Astronomical Society, 1998
- The Structure of Cold Dark Matter HalosThe Astrophysical Journal, 1996
- Nonlinear coupling of galactic spiral modesThe Astrophysical Journal, 1987