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Optical Signatures of q-deformed solution in Einstein-Maxwell-dilaton Gravity

General Relativity and Quantum Cosmology 2025-12-30 v1

Abstract

We consider null geodesics in the background of spherically symmetric object in Einstein-Maxwell-Dilaton (EMD) theory with coupling function f(Φ)=e2λΦf(\Phi)=e^{-2\lambda \Phi}. The spherical solution is characteristically described by dilaton coupling λ\lambda, integrated dilaton flux DD and magnetic charge PP. Then, we derive geodesic equations by using the Hamilton-Jacobi approach. The radial photon orbital equation on equatorial plane and effective potential are analyzed. The total deflection angle and trajectories of photon as a function of impact parameter bb are plotted with the variation of λ,D\lambda,D and PP. Furthermore, the relation between photon ring's width and the Lyapunov exponent is also explored. In addition, we use the Gralla-Lupsasca-Marrone (GLM) model to model intensity profile of optically thin accretion disk around the object. Hence, we construct optical images of the object surrounded by three distinct emission profiles. Lastly, we investigate the radius of innermost stable circular orbit (ISCO) for timelike geodesics.

Keywords

Cite

@article{arxiv.2512.23551,
  title  = {Optical Signatures of q-deformed solution in Einstein-Maxwell-dilaton Gravity},
  author = {Chawit Sakkawattana and Chatchai Promsiri and Supakchai Ponglertsakul},
  journal= {arXiv preprint arXiv:2512.23551},
  year   = {2025}
}

Comments

41 pages, 22 figures, 2 tables, 2 appendices, comments are welcome