Observational constraints on Rastall gravity from rotation curves of low surface brightness galaxies *
Meirong Tang, Zhaoyi Xu, Jiancheng Wang
Abstract
Abstract Rastall gravity is a modification of Einstein's general relativity in which the energy-momentum conservation is not satisfied and depends on the gradient of the Ricci curvature. It is currently in dispute whether Rastall gravity is equivalent to general relativity (GR). In this work, we constrain the theory using the rotation curves of low surface brightness (LSB) spiral galaxies. By fitting the rotation curves of LSB galaxies, we obtain parameter of the Rastall gravity. The values of LSB galaxies satisfy the weak energy condition (WEC) and strong energy condition (SEC). Combining the values of type Ia supernovae and the gravitational lensing of elliptical galaxies on Rastall gravity, we conclude that Rastall gravity may be equivalent to general relativity.