Issue |
A&A
Volume 432, Number 3, March IV 2005
|
|
---|---|---|
Page(s) | 771 - 781 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361:20041535 | |
Published online | 07 March 2005 |
Cosmological constraints from clustering properties of galaxy clusters
1
Boaziçi University, Physics Department, 80815 Bebek, Istanbul, Turkey e-mail: antonino.delpopolo@boun.edu.tr
2
Dipartimento di Matematica, Università Statale di Bergamo, via dei Caniana, 2, 24127, Bergamo, Italy
Received:
25
June
2004
Accepted:
19
October
2004
In this paper, we discuss improvements of the Suto et al. ([CITE]) model,
in the light of recent theoretical developments (new theoretical mass
functions, a more accurate mass-temperature relation
and an improved bias model) to predict the clustering properties of galaxy
clusters and to obtain constraints on cosmological parameters.
We re-derive the two-point correlation function of clusters of galaxies for
OCDM and ΛCDM cosmological models, and we compare these results with
the observed spatial correlation function for clusters in RASS1 (ROSAT All-Sky Survey 1), and in XBACs (X-RAY Brighest Abell-Type) samples. The comparison shows that the best agreement
is obtained for the ΛCDM model with .
The values of the correlation length obtained, (
Mpc for ΛCDM), are larger than those found in the literature and
comparable with the results found in Borgani et al.
([CITE]). In order to study the possible dependence of the clustering
properties of the X-ray clusters on the observational characteristics
defining the survey, we calculated the values of the correlation length r0
in the catalogues where we vary the limiting X-ray flux
. The
result shows
an increase of r0 with
,
and correlation lengths that are larger than in previous
papers in literature (e.g. Moscardini et al. [CITE] (hereafter MMM);
Suto et al. [CITE]).
These differences
are due essentially to the different
, mass function and bias model used
in this paper.
Then, we perform a maximum-likelihood analysis by comparing the theoretical
predictions to a set of observational data in the X-ray band (RASS1 Bright
Sample, BCS (Rosat Brightest Cluster Sample), XBACs, REFLEX (ROSAT-ESO Flux Limited X-Ray Sample)), similarly to MMM. In the framework of cold dark
matter models, we compute the constraints on cosmological parameters, such
as the matter density
, the contribution to density due
to the cosmological constant,
, the power-spectrum shape
parameter Γ and normalization
. If we fix Γ and
, at the values suggested by different observational datasets, we
obtain (for flat cosmological models with varying
cosmological constant
) constraints on the matter density parameter:
and
at the 95.4 and
99.73 per cent levels, respectively, which is 20–30% larger than the values
obtained MMM.
Leaving Γ, and
, free
for the flat model, the constraints for Γ are
, while for the open model
. These values are smaller than those of MMM by
about
%. If we keep the values of
fixed, we obtain
the constraints in the
plane.
For the open model with
the
region for Γ is 0.11–0.2 for
it is 0.7 and 1.55.
For the flat model with
the
region has
and
The
values of
obtained are larger than those of MMM by
.
If we allow the shape parameter to vary, we find that the clustering
properties of clusters are almost independent of the matter density
parameter and of the presence of a cosmological constant, while they appear
to be strongly dependent on the shape parameter.
Key words: cosmology: large-scale structure of Universe
© ESO, 2005
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