Testing EGB gravity coupled to bumblebee field and black hole parameter estimation with EHT observations

Misba Afrin, Sushant G. Ghosh, Anzhong Wang

A general covariant Einstein-Gauss-Bonnet Gravity in Four-Dimensional (4D EGB) spacetime is shown to bypass Lovelock's theorem and is free from Ostrogradsky instability. Meanwhile,…