Some optical properties of rotating wormhole in Bopp-Podolsky electrodynamics

TL;DR

This work constructs a rotating Morris-Thorne-type wormhole sourced by Bopp-Podolsky electrodynamics by applying Azreg-Ainou’s rotating algorithm to a static BP wormhole. The authors analyze null geodesics, shadows, and strong-field gravitational lensing in the equatorial plane, deriving the effective potential, photon-orbit structure, and observable lensing quantities. They find that shadows can be smooth or cuspy depending on the spin $a$ and BP parameters $Q$ and $b$, with cusps arising from the merger of inner throat and outer photon-orbit families at high spin; strong-lensing observables such as $ heta_ ext{∞}$, $s$, and $r_ ext{mag}$ depend on $a$, $Q$, and $b$, while degeneracies with black-hole lensing pose observational challenges for distinguishing such wormholes from BHs. The results highlight the viability of BP wormholes and provide signatures in shadow and strong-lensing observables that can guide future observational constraints on wormhole spacetimes in modified electrodynamics.

Abstract

In this work, we consider a static wormhole in Bopp-Podolsky electrodynamics and convert it into its rotating counterpart by reducing it into Morris-Thorne form. We further study the null geodesics and effective potential along with the shadows for inner and outer unstable orbits for specific choices of parameters. It is found that for some cases smooth shadow curves are formed and for a few cases, the shadows formed are cuspy. All parameters have a significant impact on the shadows except for the parameter $b$ when either $a$ or $Q$ are kept small. We also analyze the gravitational lensing in the strong regime, considering that the observer and the source are on opposite sides of the throat. For this situation, we explore in detail the behavior of the deflection angle, Einstein rings and lensing observables.

Figures (9)

• Figure 1: The behavior of $f(r)$ and $g(r)$ vs $r$ for different values of $b$ and $Q$ with $M=1$.
• Figure 2: Effective potential curves showing the behavior of unstable circular null orbits for different values of $Q$, $b$ and $a$ corresponding to each curve in respective plots with $M=1$.
• Figure 3: Variation of $Q$ for each curve showing the variation in shadows in celestial plane $\alpha$-$\beta$ for different values of $b$ and fixed $a$ in upper panel, and for different values of $a$ and fixed $b$ in lower panel with $M=1$.
• Figure 4: Shadow plots for different values of $b$ corresponding to each curve while keeping $a$ fixed and varying $Q$ in upper panel, and keeping $Q$ fixed and varying $a$ in lower panel with $M=1$.
• Figure 5: Behavior of $a$ corresponding to each shadow curve for different $Q$ and fixed $b$ in upper panel, and different $b$ and fixed $Q$ with $M=1$.