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| Paper: |
The Role of Proto--Dwarf Galaxies in the Formation of Galaxy Disk |
| Volume: |
275, Disks of Galaxies: Kinematics, Dynamics and Perturbations |
| Page: |
413 |
| Authors: |
Williams, P. R.; Nelson, A. H. |
| Abstract: |
Numerical simulations including gas dynamics and star formation have suggested that dwarf galaxies may play a crucial role in the formation of the disks of grand design galaxies (see Williams & Nelson 2001). In a series of high resolution simulations aimed at investigating this phenomena further, simple solid body rotation-uniform density sphere initial conditions were used, including a spectrum of low amplitude Poisson noise, which proved successful in producing numerical galaxies which have both comparable gross structural features to contemporary bright galaxies, and a similar number of dwarf companions. The formation and evolution of the populations of dwarf galaxies in these simulations developed as follows. During the latter stages of proto-galactic collapse, a small number of fragments of roughly a few kpc in size, and of typically a few 109 Modot in mass, along with a population of smaller objects, decoupled from their local fluid flows. During the ensuing 1-2 Gyr, these fragments locally collapsed, and provided sites of high gas density where the vast majority of the early star formation activity occurred (see below left, showing gas and star particles at simulation time T=7.57 Gyr). As these clumpy gaseous fragments developed stellar components and evolved into proto-dwarfs, merger and interaction decreased their number and dispersed their stellar mass throughout the proto-disk (see below centre, T=7.94 Gyr). As the merger activity died away, a small number of now gas poor dwarfs remained on stable orbits (below right, T=9.93 Gyr). |
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