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Effect of primordial non-Gaussianities on galaxy clusters scaling relations

A. M. M. Trindade, A. C. da Silva

Abstract
Galaxy clusters are a valuable source of cosmological information. Their formation and evolution depends on the underlying cosmology and on the statistical nature of the primordial density fluctuations. Here we investigate the impact of primordial non-Gaussianities (PNG) on the scaling properties of galaxy clusters. We performed a series of hydrodynamic N-body simulations featuring adiabatic gas physics and different levels of non-Gaussianity within the Lambda cold dark matter framework. We focus on the T-M, S-M, Y-M and Y-X-M scalings relating the total cluster mass with temperature, entropy and Sunyaev-Zeld'ovich integrated pressure that reflect the thermodynamic state of the intracluster medium. Our results show that PNG have an impact on cluster scalings laws. The scalings mass power-law indexes are almost unaffected by the existence of PNG, but the amplitude and redshift evolution of their normalizations are clearly affected. Changes in the Y-M and Y-X-M normalizations are as high as 22 per cent and 16 per cent when f(NL) varies from -500 to 500, respectively. Results are consistent with the view that positive/negative f(NL) affect cluster profiles due to an increase/decrease of cluster concentrations. At low values of f(NL), as suggested by present Planck constraints on a scale invariant f(NL), the impact on the scaling normalizations is only a few per cent. However, if f(NL) varies with scale, PNG may have larger amplitudes at clusters scales; thus, our results suggest that PNG should be taken into account when cluster data are used to infer or forecast cosmological parameters from existing or future cluster surveys.

Keywords
methods: numerical, cosmological parameters, large-scale structure of Universe

Monthly Notices of the Royal Astronomical Society
Volume 469, Issue 1, Page 551
2017 July

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Instituto de Astrofísica e Ciências do Espaço Universidade do Porto Faculdade de Ciências da Universidade de Lisboa Fundação para a Ciência e a Tecnologia