Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A ∗

Abstract Horizon-scale images of black holes (BHs) and their shadows have opened an unprecedented window onto tests of gravity and fundamental physics in the strong-field regime. We demonstrate that the EHT image of Sgr A <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mi/> <mml:mo>∗</mml:mo> </mml:msup> </mml:math> places particularly stringent constraints on models predicting a shadow size larger than that of a Schwarzschild BH of a given mass, with...

⚡ This is an original paraphrased summary — not copied from the abstract. Full paper available at the source link below.

• 1 We consider a wide range of well-motivated deviations from classical general relativity (GR) BH solutions, and constrain them using the Event Horizon Telescope (EHT) observations of Sagittarius A <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mi/> <mml:mo>∗</mml:mo> </mml:msup> </mml:math> (Sgr A <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mi> </mml:mi> <mml:mo>∗</mml:mo> </mml:msup> </mml:math> ), connecting the size of the bright ring of emission to that of the underlying BH shadow and exploiting high-precision measurements of Sgr A <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mi> </mml:mi> <mml:mo>∗</mml:mo> </mml:msup> </mml:math> ’s mass-to-distance ratio.
• 2 The scenarios we consider, and whose fundamental parameters we constrain, include various regular BHs, string-inspired space-times, violations of the no-hair theorem driven by additional fields, alternative theories of gravity, novel fundamental physics frameworks, and BH mimickers including well-motivated wormhole and naked singularity space-times.
• 3 We demonstrate that the EHT image of Sgr A <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mi/> <mml:mo>∗</mml:mo> </mml:msup> </mml:math> places particularly stringent constraints on models predicting a shadow size larger than that of a Schwarzschild BH of a given mass, with the resulting limits in some cases surpassing cosmological ones.

This work deepens our understanding of the fundamental laws governing the universe, from subatomic particles to cosmic structures.

This summary is based on publicly available metadata and abstract. For the full research paper, visit the original source: