Solar system constraints on asymptotically flat IR modified Horava gravity through light deflection

TL;DR

This study derives constraints on IR modified Hořava gravity using light deflection measurements around black holes, showing how the deflection angle varies with the gravity parameter and matching observations within certain bounds.

Contribution

The paper provides an analytic formula for light deflection in Hořava gravity and establishes observational constraints from solar system data.

Findings

Deflection angle increases with the gravity parameter ω.

At UV limit, deflection matches Schwarzschild prediction.

Constraints on ω M^2 are derived for Earth, Jupiter, and solar system observations.

Abstract

In this paper, we study the motion of photons around a Kehagias-Sfetsos (KS) black hole and obtain constraints on IR modified Ho$\check{r}$ava gravity without cosmological constant ($\sim \Lambda_{W}$). An analytic formula for the light deflection angle is obtained. For a propagating photon, the deflection angle $\delta \phi$ increases with large values of the Ho$\check{r}$ava gravity parameter $\omega$. Under the UV limit $\omega \longrightarrow \infty$, deflection angle reduces to the result of usual Schwarzschild case, $4GM/R$. It is also found that with increasing scale of astronomical observation system the Ho$\check{r}$ava-Lifshitz gravity should satisfy $|\omega M^2|>1.1725 \times10^{-16}$ with 12% precision for Earth system, $|\omega M^2| > 8.27649 \times 10^{-17}$ with 17% precision for Jupiter system and $|\omega M^2| > 8.27650\times 10^{-15}$ with 0.17% precision for solar system.