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| Paper: |
Halo evolution in Hierarchical Cosmogonies |
| Volume: |
92, Formation of the Galactic Halo. . . . Inside and Out |
| Page: |
505 |
| Authors: |
Rodrigues, D. D. C.; Thomas, P. A. |
| Abstract: |
A new method has been developed to calculate the merger history of dark matter halos in hierarchical cosmogonies. Our procedure involves smoothing the initial density field within cubical blocks of a range of scales, and ordering them in decreasing density. On each mass scale the method uses a series of overlapping grids so that the likehood of finding rare high-mass peaks is increased. The mapping of the resulting ensemble of overlapping blocks into a set of disjoint, overdense structures, each of each will form a single virialized halo, is governed by a set of merging rules acting upon the degree of overlap between the blocks. A merger tree is then constructed to express the collapse history of the blocks. We are not limited to masses which are a power of two, unlike the Block model of Cole & Kaiser, and our scheme is based on an actual realization of the density field. We show that our model exhibits the required scaling behaviour when tested on power-law spectra of density fluctuations, but that it predicts far more massive halos for flat spectra than does the Press-Schechter formalism. This model constitutes the basis for future semi-analytic galaxy formation studies. |
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