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Centro de Astrofísica da Universidade do Porto

Cluster scaling relations from cosmological hydrodynamic simulations in a dark energy dominated universe

N. Aghanim, A. C. da Silva, N. J. Nunes

Abstract
Context. Clusters are potentially powerful tools for cosmology provided their observed properties such as the Sunyaev-Zel’dovich (SZ) or X-ray signals can be translated into physical quantities like mass and temperature. Scaling relations are the appropriate mean to perform this translation. It is therefore, important to understand their evolution and their modifications with respect to the physics and to the underlying cosmology.
Aims. In this spirit, we investigate the effect of dark energy on the X-ray and SZ scaling relations. The study is based on the first hydro simulations of cluster formation for diferent models of dark energy. We present results for four dark energy models which differ from each other by their equations of state parameter, w. Namely, we use a cosmological constant model w = −1 (as a reference), a perfect fluid with constant equation of state parameter w = −0.8 and one with w = −1.2 and a scalar field model (or quintessence) with varying w.
Methods. We generate N-body/hydrodynamic simulations that include radiative cooling with the public version of the Hydra code, modified to consider an arbitrary dark energy component. We produce cluster catalogues for the four models and derive the associated X-ray and SZ scaling relations.
Results. We find that dark energy has little effect on scaling laws making it safe to use the ΛCDM scalings for conversion of observed quantities into temperature and masses.

Keywords
large-scale structure of Universe

Astronomy and Astrophysics
Volume 496, Page 637
March 2009

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