The radial acceleration relation in galaxy clusters

Abstract: Recently, the discovery of the radial acceleration relation (RAR) in galaxies has been regarded as an indirect support of alternative theories of gravity such as Modified Newtonian Dynamics (MOND) and modified gravity. This relation indicates a tight correlation between dynamical mass and baryonic mass in galaxies with different sizes and morphology. However, if the RAR relation is scale-independent and could be explained by alternative theories of gravity, this relation should be universal and true for galaxy clusters as well. In this article, by using the x-ray data of a sample of galaxy clusters, we investigate if there exists any tight correlation between dynamical mass and baryonic mass in galaxy clusters, assuming hot gas mass distribution almost representing baryonic distribution and that the galaxy clusters are virialized. We show that the resulting RAR of 52 non-cool-core galaxy clusters scatters in a large parameter space, possibly due to our simplifying assumptions and unclear matter content in galaxy clusters. This might indicate that the RAR is unlikely to be universal and scale-independent.