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Geometric Approach to Circular Photon Orbits and Black Hole Shadows

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arxiv 2204.07297 v3 pith:IV3O744M submitted 2022-04-15 gr-qc math-phmath.MP

Geometric Approach to Circular Photon Orbits and Black Hole Shadows

classification gr-qc math-phmath.MP
keywords approachblackcircularholephotongeometricorbitseffective
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
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Circular photon orbit and black hole shadow are significantly important issues in physics and astronomy, and a number of breakthroughs have been witnessed in recent years. Conventionally, the stable and unstable circular photon orbits are obtained using the effective potential of test particles moving in black hole spacetime. In this work, a pure geometric approach is developed to calculate these circular photon orbits and black hole shadow radius. Furthermore, it can be proved that our geometric approach is completely equivalent to the conventional approach based on effective potentials of test particles.

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Cited by 5 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. A perturbative geometric approach for photon spheres, massive particle surfaces and black hole shadows with mass variations

    gr-qc 2026-05 unverdicted novelty 5.0

    Presents a curvature-based perturbative method for photon spheres, massive particle surfaces, and black hole shadows that handles mass variations and claims new results for the time-like case.

  2. Photon Spheres and shadow of modified black-hole entropies

    gr-qc 2026-05 unverdicted novelty 4.0

    Modified black hole entropies alter photon sphere radii and shadow sizes, with parameters constrained by Event Horizon Telescope observations of Sgr A*.

  3. Photon Spheres and shadow of modified black-hole entropies

    gr-qc 2026-05 unverdicted novelty 4.0

    Corrected black hole entropies produce distinct shifts in photon sphere radius and shadow size that are constrained by Event Horizon Telescope data on Sagittarius A*.

  4. Photon Spheres and shadow of modified black-hole entropies

    gr-qc 2026-05 unverdicted novelty 4.0

    Entropy corrections to black holes produce modified metrics whose photon-sphere and shadow sizes can be constrained by Sgr A* observations.

  5. Gaussian curvature and Lyapunov exponent as probes of black hole phase transitions

    gr-qc 2025-09 conditional novelty 4.0

    Gaussian curvature at the light ring inherits the swallowtail multivaluedness of free energy in first-order black hole phase transitions, following directly from K = -λ².