Abstract
A&A 584, A57 (2015) In this paper we study the effects of letting the dark matter and the 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. The
research is performed utilising a series of hydrodynamic, cosmological N-Body
simulations, studying the resulting power spectra and galaxy halo properties,
such as the density and temperature profiles. Results show that in the cases of
universal couplings, the deviations in the baryon fraction from $\Lambda$CDM
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 $\Lambda$CDM reference values can differ significantly between
dark matter and gas because the dark matter deviations are mostly larger than
the deviations in the gas.