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Issue A&A
Volume 424, Number 2, September III 2004
Page(s) 415 - 428
Section Cosmology (including clusters of galaxies)
DOI 10.1051/0004-6361:20034107



A&A 424, 415-428 (2004)
DOI: 10.1051/0004-6361:20034107

Dark energy versus $\Omega\mathsf = 1}$ in the growth of matter perturbations

M. Membrado1 and J. A. L. Aguerri2

1  Departamento de Física Teórica, Universidad de Zaragoza, 50009 Zaragoza, Spain
    e-mail: membrado@unizar.es
2  Instituto de Astrofísica de Canarias, 38200 La Laguna, Spain
    e-mail: jalfonso@ll.iac.es

(Received 24 July 2003 / Accepted 2 June 2004 )

Abstract
We explore the possibility of discriminating dark energy models from the study of the growth of matter perturbations. For the sake of simplicity, instead of dealing with a great number of models, we have chosen a simple model of dark energy ( $p_x=\omega_0\rho_{x}^{\gamma}$, with $\omega_0<0$ and $\gamma>0$; px, and $\rho_x$ being pressure and energy density), which is able to reproduce a great number of different behaviours. A combination of WMAP data with other results have been used to estimate model parameters. The study has been made for collapsing shells in spherical clusters virialized at redshifts z=1, 0.1 and 0.025 with line-of-sight velocity dispersion $\sigma_{\rm los}= 750$ and $1000~\rm km\, s^$. According to shell velocities, our dark energy models are clearly differentiated from the $\Omega_{\rm m0}=1$ model (the greater the $\sigma_{\rm los}$ is, the more differentiated the models are). However, the differences among dark energy models are not so large. From our results, the nearest clusters with large $\sigma_{\rm los}$ are the idoneous ones to discriminate models. In fact, we think that from observations of caustics in nearby spherical clusters, it would be possible to make an estimation of  $\Omega_{\rm m0}$.


Key words: cosmology: theory




© ESO 2004


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