Black Hole Shadows Constrain Extended Gravity

The first images of black hole shadows open new possibilities to constrain modern extended gravity theories. We present the method shadow background calculation for solutions in form Taylor series where g11 = – $$g_{{00}}^{{ - 1}}$$ . is general nonrotating case ≠ results analysis are compared with predictions General relativity taking into account Event Horizon Telescope data. Horndesky model Gauss–Bonnet invariant, loop quantum gravity, Bumblebee and full agreement observations M87*. In conformal large values m2 Qs must be excluded. STEGR f(Q) observational limits on parameter α are: –0.025 < 0.04. For an alternative generalization Schwarzschild approximation: –0.3 l 0.45. These demonstrate maximum one can achieve without rotation a hole.