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Event Horizon Telescope observations exclude compact objects in baseline mimetic gravity.

Mohsen Khodadi1, Sunny Vagnozzi2,3, Javad T Firouzjaee1,4,5

  • 1Department of Physics, K. N. Toosi University of Technology, P. O. Box 15875-4416, Tehran, Iran.

Scientific Reports
|November 6, 2024
PubMed
Summary

Mimetic gravity, a theory explaining cosmic phenomena, fails to match observations. Its black hole and naked singularity models do not accurately predict observed black hole shadows, ruling out this version of the theory.

Keywords:
Black hole shadowsBlack holesCosmologyMimetic gravityNaked singularities

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Area of Science:

  • Cosmology
  • General Relativity
  • Theoretical Physics

Background:

  • Mimetic gravity is a modified gravity theory proposed to explain cosmological observations.
  • Static, spherically symmetric spacetimes in mimetic gravity present challenges, yielding only a naked singularity or a black hole spacetime.

Purpose of the Study:

  • To investigate the shadow properties of spacetimes predicted by the baseline mimetic gravity theory.
  • To assess the viability of mimetic gravity in light of observational data from the Event Horizon Telescope.

Main Methods:

  • Analysis of the shadow characteristics of the naked singularity and black hole solutions in mimetic gravity.
  • Comparison of theoretical shadow predictions with observational data of M87* and Sgr A*.

Main Results:

  • The naked singularity in mimetic gravity does not cast a shadow.
  • The black hole solution casts a shadow that is observably too small.
  • These findings are inconsistent with Event Horizon Telescope observations.

Conclusions:

  • The baseline mimetic gravity theory is inconsistent with current astronomical observations of black hole shadows.
  • Event Horizon Telescope data effectively rules out this version of mimetic gravity for explaining cosmological dark sector phenomena.
  • There is a significant interplay between black hole imaging and the development of modified gravity theories.