EDP Sciences
Free Access
Volume 416, Number 3, March IV 2004
Page(s) 853 - 864
Section Cosmology (including clusters of galaxies)
DOI https://doi.org/10.1051/0004-6361:20031757

A&A 416, 853-864 (2004)
DOI: 10.1051/0004-6361:20031757

Numerical study of halo concentrations in dark-energy cosmologies

K. Dolag1, M. Bartelmann2, F. Perrotta3, 4, C. Baccigalupi3, 4, L. Moscardini5, M. Meneghetti1 and G. Tormen1

1  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

(Received 18 August 2003 / 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" $\Lambda$CDM 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 $(1+z)\,c=c_0\,(M/M_0)^\alpha$, with $\alpha\approx-0.1$ throughout. We find that the cluster concentration depends on the dark energy equation of state at the cluster formation redshift $z_{\rm coll}$ through the linear growth factor $D_+(z_{\rm coll})$. As a simple correction accounting for dark-energy cosmologies, we propose scaling c0 from $\Lambda$CDM with the ratio of linear growth factors, $c_0\rightarrow
c_0\,D_+(z_{\rm coll})/D_{+,~\Lambda{\rm CDM}}(z_{\rm coll})$ .

Key words: galaxies: clusters: general -- galaxies: halos -- cosmology: theory

Offprint request: K. Dolag, kdolag@pd.astro.it

© ESO 2004

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.