Rotating Black Holes in Horndeski Gravity: Thermodynamic and Gravitational Lensing

Understand

The lack of rotating black holes, typically found in nature, hinders testing modified gravity from astrophysical observations.

• We present the axially symmetric counterpart of an existing spherical hairy black hole in Horndeski gravity having an additional deviation parameter $Q$, which encompasses the Kerr black hole as a particular case ($Q=0$).
• We investigate the effect of Horndeski parameter $Q$ on the rotating black holes' geometry and analytically deduce the gravitational deflection angle of light in the weak-field limit.
• For the S2 source star, the deflection angle for the Sgr A* model of the rotating Horndeski gravity black hole for both prograde and retrograde photons is larger than the Kerr black hole values.