Volume 454, Number 1, July IV 2006
|Page(s)||17 - 26|
|Section||Cosmology (including clusters of galaxies)|
|Published online||03 July 2006|
Some improvements to the spherical collapse model
Boǧaziçi University, Physics Department, 80815 Bebek, Istanbul, Turkey e-mail: email@example.com Dipartimento di Matematica, Università Statale di Bergamo, via dei Caniana, 2, 24127, Bergamo, Italy Istanbul Technical University, Ayazaga Campus, Faculty of Science and Letters, 34469 Maslak/Istanbul, Turkey
Accepted: 21 February 2006
I study the joint effect of dynamical friction, tidal torques and cosmological constant on clusters of galaxies formation. I show that within high-density environments, such as rich clusters of galaxies, both dynamical friction and tidal torques slows down the collapse of low-ν peaks producing an observable variation in the time of collapse of the perturbation and, as a consequence, a reduction in the mass bound to the collapsed perturbation. Moreover, the delay of the collapse produces a tendency for less dense regions to accrete less mass, with respect to a classical spherical model, inducing a biasing of over-dense regions toward higher mass. I show how the threshold of collapse is modified if dynamical friction, tidal torques and a non-zero cosmological constant are taken into account and I use the Extended Press Schecter (EPS) approach to calculate the effects on the mass function. Then, I compare the numerical mass function given in Reed et al. (2003) with the theoretical mass function obtained in the present paper. I show that the barrier obtained in the present paper gives rise to a better description of the mass function evolution with respect to other previous models (Sheth & Tormen 1999, MNRAS, 308, 119 (hereafter ST); Sheth & Tormen 2002, MNRAS, 329, 61 (hereafter ST1)).
Key words: cosmology: large scale structure of Universe
© ESO, 2006
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.