Exploring the presence of a fifth force at the Galactic Center

Aims. We investigate the presence of a Yukawa-like correction to Newtonian gravity at the Galactic Center, leading to a new upper limit on the intensity of such a correction. Methods. We performed a Markov chain Monte Carlo (MCMC) analysis using the astrometric and spectroscopic data of star S2 collected at the Very Large Telescope by GRAVITY, NACO, and SINFONI instruments, covering the period from 1992 to 2022. Results. The precision of the GRAVITY instrument allows us to derive the most stringent upper limit at the Galactic Center for the intensity of the Yukawa contribution (∝ αe−λr) of |α|< 0.003 for a scale length of λ = 3 ⋅ 1013 m (∼ 200 AU). This is an improvement on all estimates obtained in previous works by roughly one order of magnitude.