The spherical-collapse model predicts collapse when a linearly extrapolated smoothed overdensity exceeds the threshold in an Einstein-de Sitter universe.
The peak height of a halo of mass is , where is the variance of the linear density field smoothed on the corresponding mass scale.
The Press-Schechter formalism estimates the halo abundance from the Gaussian probability that a smoothed linear overdensity crosses the spherical-collapse threshold, with a factor of two enforcing total mass conservation.
The Press-Schechter differential abundance is
Articles by others on the same topic
The Spherical Collapse Model is a theoretical framework used in cosmology to understand the formation of structure in the universe, particularly galaxies and galaxy clusters. It provides a simplified way to study how density perturbations evolve under the influence of gravitational collapse. ### Key Features of the Spherical Collapse Model: 1. **Initial Conditions**: - The model starts with an initial density perturbation, often assumed to be spherically symmetric.