Galaxy formation and the peaks formalism

Abstract

A large N-body simulation is used to compare the galaxies found by tagging peaks in the linear density field with the haloes that actually form. A variety of filters on the density field are tried in order to improve this correspondence, but none seems to do particularly well. The correlation function and velocity dispersion of the tagged peaks and the actual haloes also do not correspond very well. These comparisons bring into question the results of any study of galaxy formation that assumes that galaxies form at peaks in the initial density field, or simulations of large-scale structure that use the high-peak model to determine the galaxy distribution.