Testing Emergent Gravity with Optical, X-Ray, and Weak Lensing Measurements in Massive, Relaxed Galaxy Clusters
We test the predictions of emergent gravity (EG) using matter densities of relaxed, massive clusters of galaxies observed from optical and X-ray wavebands. We improve upon previous work in this area by including the baryon mass contribution of the brightest cluster galaxy (BCG) in each system, in addition to total mass profiles from gravitational lensing and mass profiles of the X-ray emitting gas from Chandra. We use this data in the context of EG to predict the “apparent” dark matter (DM) distribution from the observed baryon distribution, and vice versa. We find that although the inclusion of the BCG in the analysis improves the agreement with observations in the inner regions of the clusters ( kpc), at larger radii ( kpc) the EG predictions for mass profiles and baryon mass fractions are not in agreement with observations by a factor of up to ∼2−6, though the agreement improves at radii near r500. At least in its current form, EG does not appear to reproduce the observed characteristics of relaxed galaxy clusters as well as cold DM models.