Cosmological simulations with hydrodynamics of screened scalar-tensor gravity with non-universal coupling

Institute of Theoretical Astrophysics, University of Oslo, PO Box 1029 Blindern, 0315 Oslo, Norway
e-mail: amirham@astro.uio.no; d.f.mota@astro.uio.no

Received: 26 May 2015
Accepted: 2 October 2015

Abstract

Aims. We study the effects of letting dark matter and gas in the Universe couple to the scalar field of the symmetron model, a modified gravity theory, with varying coupling strength. We also search for a way to distinguish between universal and non-universal couplings in observations.

Methods. The research is performed utilising a series of hydrodynamic, cosmological N-Body simulations, studying the resulting power spectra and galaxy halo properties, such as density and temperature profiles.

Results. In the cases of universal couplings, the deviations in the baryon fraction from ΛCDM are smaller than in the cases of non-universal couplings throughout the halos. The same is apparent in the power spectrum baryon bias, defined as the ratio of gas to dark matter power spectrum. Deviations of the density profiles and power spectra from the ΛCDM reference values can differ significantly between dark matter and gas because the dark matter deviations are mostly larger than the deviations in the gas.