摘要：We use cosmological hydrodynamical simulations to study the effect of screened modified
gravity models on the mass estimates of galaxy clusters. In particular, we focus on two
novel aspects: (i) we study modified gravity models in which baryons and dark matter are
coupled with different strengths to the scalar field, and; (ii) we put the simulation
results into the greater context of a general screened-modified gravity parametrization.
We have compared the mass of clusters inferred via lensing versus the mass inferred via
kinematical measurements as a probe of violations of the equivalence principle at Mpc
scales. We find that estimates of cluster masses via X-ray observations is mainly
sensitive to the coupling between the scalar degree of freedom and baryons – while the
kinematical mass is mainly sensitive to the coupling to dark matter. Therefore, the
relation between the two mass estimates is a probe of a possible non-universal coupling
between the scalar field, the standard model fields, and dark matter. Finally, we used
observational data of kinetic, thermal and lensing masses to place constraints on
deviations from general relativity on cluster scales for a general parametrization of
screened modified gravity theories which contains f(R) and
Symmetron models. We find that while the kinematic mass can be used to place competitive
constraints, using thermal measurements is challenging as a potential non-thermal
contribution is degenerate with the imprint of modified gravity.
关键词：large-scale structure of Universe;dark energy;gravitation;galaxies: clusters: general;X-rays: galaxies: clusters;galaxies: kinematics and dynamics
