Aether Scalar Tensor theory confronted with weak lensing data at small accelerations

Abstract

Context. The recently-proposed Aether Scalar Tensor (AeST) model reproduces both the successes of particle dark matter on cosmological scales and those of Modified Newtonian Dynamics (MOND) on galactic scales. But the AeST model reproduces MOND only up to a certain maximum galactocentric radius. Since MOND is known to fit very well to observations at these scales, this raises the question whether the AeST model comes into tension with data. Aims. We test whether or not the AeST model is in conflict with observations using a recent analysis of data for weak gravitational lensing. Methods. We solve the equations of motion of the AeST model, analyze the solutions' behavior, and compare the results to observational data.Results. The AeST model shows some deviations from MOND at the radii probed by weak gravitational lensing. This creates a tension with the data. To entirely rule out the model, however, a more advanced data analysis as well as an improved theoretical understanding would be necessary.