Volume 416, Number 3, March IV 2004
|Page(s)||853 - 864|
|Section||Cosmology (including clusters of galaxies)|
|Published online||09 March 2004|
Numerical study of halo concentrations in dark-energy cosmologies
Dipartimento di Astronomia, Università di Padova, Italy
2 Max-Planck-Institut für Astrophysik, PO Box 1317, 85741 Garching, Germany
3 SISSA, Trieste, Italy
4 Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
5 Dipartimento di Astronomia, Università di Bologna, Italy
Corresponding author: K. Dolag, email@example.com
Accepted: 2 December 2003
We study the concentration parameters, their mass dependence and redshift evolution, of dark-matter halos in different dark-energy cosmologies with constant and time-variable equation of state, and compare them with “standard” ΛCDM and OCDM models. We find that previously proposed algorithms for predicting halo concentrations can be well adapted to dark-energy models. When centred on the analytically expected values, halo concentrations show a log-normal distribution with a uniform standard deviation of ~0.2. The dependence of averaged halo concentrations on mass and redshift permits a simple fit of the form , with throughout. We find that the cluster concentration depends on the dark energy equation of state at the cluster formation redshift zcoll through the linear growth factor . As a simple correction accounting for dark-energy cosmologies, we propose scaling c0 from ΛCDM with the ratio of linear growth factors, .
Key words: galaxies: clusters: general / galaxies: halos / cosmology: theory
© ESO, 2004
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