Constraining MOdified Gravity with the S2 Star

TL;DR

This study uses the S2 star's orbital data to place new constraints on a modified gravity theory, specifically limiting the fractional change in the gravitational constant near the Galactic Centre.

Contribution

First to constrain the parameter of a modified gravity theory using S2 star data through geodesic integration and MCMC analysis.

Findings

lpha 0.662 at 99.7% confidence level

Provided the first constraint on the scale of the Galactic Centre for this theory

Demonstrated the effectiveness of orbital data in testing modified gravity

Abstract

We have used publicly available kinematic data for the S2 star to constrain the parameter space of MOdified Gravity. Integrating geodesics and using a Markov Chain Monte Carlo algorithm we have provided with the first constraint on the scales of the Galactic Centre for the parameter $\alpha$ of the theory, which represents the fractional increment of the gravitational constant $G$ with respect to its Newtonian value. Namely, $\alpha \lesssim 0.662$ at 99.7% confidence level (where $\alpha = 0$ reduces the theory to General Relativity).