Radiation properties and images of loop quantum Reissner-Nordström black hole with a thin accretion disk

Abstract

We investigate the characteristics of circular motion of charged particles around loop quantum Reissner-Nordström black hole (LQRNBH) and the radiation properties and observational appearance of a thin accretion disk around it. By calculating the shadow radius and utilizing observational data from M87* and Sgr A*, we derive constraints on the quantum parameter $ζ$ and charge parameter $Q$. In order to support a accretion disk around the black hole, the charge parameter $Q$ is restricted to be tiny ($Q\lesssim10^{-21}$). The circular motion of charged particles around LQRNBH and the influence of the model parameters on the circular motion are studied. It is found that although the direct charge correction to the geometry is negligible, the electromagnetic coupling $κ$ substantially impacts the circular motion and the radiative properties. Then, by considering a thin accretion disk model, the local radiation fluxes, redshift factors and the observed fluxes are studied. With the ray-tracing method, the isoradial curves, direct images of redshift factors and the observed fluxes are illustrated. The influence of the model parameters on these quantities are systematically performed. It is found that the influence of the quantum parameter $ζ$ is generally very small but whether its a positive or negative effect depends on the sign of $κ$, i.e. attractive or repulsive electromagnetic force. Although the charge of the black hole is tiny in our study, the electromagnetic interaction generally has significant influence on the physical quantities.