Observational test of ${\mathcal{R}}^2$ spacetimes with the S2 star in the Milky Way galactic center

Jian-Ming Yan, Tao Zhu, Mustapha Azreg-Aïnou +2

A novel class of vacuum metrics expressible in analytical form was recently found for pure ${\mathcal{R}}^2$ gravity, based on a groundwork put forth by Buchdahl in 1962. These Buchda…