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Event Horizon Telescope observations exclude compact objects in baseline mimetic gravity

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arxiv 2408.03241 v2 pith:HXQOKODZ submitted 2024-08-06 gr-qc astro-ph.COhep-phhep-th

Event Horizon Telescope observations exclude compact objects in baseline mimetic gravity

classification gr-qc astro-ph.COhep-phhep-th
keywords gravitybaselineblackcosmologicalholemimeticshadowevent
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
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abstract

Mimetic gravity has gained significant appeal in cosmological contexts, but static spherically symmetric space-times within the baseline theory are highly non-trivial: the two natural solutions are a naked singularity and a black hole space-time obtained through an appropriate gluing procedure. We study the shadow properties of these two objects, finding both to be pathological. In particular, the naked singularity does not cast a shadow, whereas the black hole casts a shadow which is too small. We argue that the Event Horizon Telescope images of M87$^{\star}$ and Sgr A$^{\star}$ rule out the baseline version of mimetic gravity, preventing the theory from successfully accounting for the dark sector on cosmological scales. Our results highlight an interesting complementarity between black hole imaging observations and modified gravity theories of cosmological interest.

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Cited by 5 Pith papers

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    gr-qc 2026-06 unverdicted novelty 5.0

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  3. 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*.

  4. 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*.

  5. 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.