In this paper, we construct an effective rotating loop quantum black hole (LQBH) solution, starting from the spherical symmetric LQBH by applying the Newman-Janis algorithm modified by Azreg-Aïnou’s noncomplexification procedure, and study the effects of loop quantum gravity (LQG) on its shadow. Given the rotating LQBH, we discuss its horizon, ergosurface, and regularity as $r\to 0$. Depending on the values of the specific angular momentum $a$ and the polymeric function $P$ arising from LQG, we find that the rotating solution we obtained can represent a regular black hole, a regular extreme black hole, or a regular spacetime without horizon (a non-black-hole solution). We also study the effects of LQG and rotation, and show that, in addition to the specific angular momentum, the polymeric function also causes deformations in the size and shape of the black hole shadow. Interestingly, for a given value of $a$ and inclination angle ${\theta }_0$, the apparent size of the shadow monotonically decreases, and the shadow gets more distorted with increasing $P$. We also consider the effects of $P$ on the deviations from the circularity of the shadow, and find that the deviation from circularity increases with increasing $P$ for fixed values of $a$ and ${\theta }_0$. Additionally, we explore the observational implications of $P$ in comparing with the latest Event Horizon Telescope observation of the supermassive black hole, M87*. The connection between the shadow radius and quasinormal modes in the eikonal limit as well as the deflection of massive particles are also considered.

• Received 18 February 2020
• Accepted 16 March 2020

DOI:https://doi.org/10.1103/PhysRevD.101.084001