Probing Geometric Proca in Metric-Palatini Gravity with Black Hole Shadow and Photon Motion

Abstract

Extended metric-Palatini gravity, quadratic in the antisymmetric part of the affine curvature, is known to lead to the general relativity plus a geometric Proca field. The geometric Proca, equivalent of the non-metricity vector in the torsion-free affine connection, qualifies to be a distinctive signature of the affine curvature. In the present work, we explore how shadow and photon motion near black holes can be used to probe the geometric Proca field. To this end, we derive static spherically symmetric field equations of this Einstein-geometric Proca theory, and show that it admits black hole solutions in asymptotically AdS background. We perform a detailed study of the optical properties and shadow of this black hole and contrast them with the observational data by considering black hole environments with and without plasma. As a useful astrophysical application, we discuss constraints on the Proca field parameters using the observed angular size of the shadow of supermassive black holes M87${}^{\ast }$ and Sgr A${}^{\ast }$ in both vacuum and plasma cases. Overall, we find that the geometric Proca can be probed via the black hole observations.

19 pages, 14 figures. To appear in European Physical Journal C

References in corpus (22)

• Measurement of the Kerr Spin Parameter by Observation of a Compact Object's Shadow
• Relativistic images of Schwarzschild black hole lensing
• Apparent shape of super-spinning black holes
• Metric-affine f(R) theories of gravity
• Null geodesics and shadow of a rotating black hole in extended Chern-Simons modified gravity
• Inflation with Non-Minimal Coupling: Metric vs. Palatini Formulations
• Shadow of five-dimensional rotating Myers-Perry black hole
• Wormholes supported by hybrid metric-Palatini gravity
• Shadow of a Kaluza-Klein rotating dilaton black hole
• Shadows of Einstein-dilaton-Gauss-Bonnet black holes
• Frequency-dependent effects of gravitational lensing within plasma
• Higgs-Palatini Inflation and Unitarity
• Shadows and gravitational weak lensing by the Schwarzschild black hole in the string cloud background with quintessential field
• Cosmology of hybrid metric-Palatini f(X)-gravity
• Fourth order Weyl gravity
• Axion-plasmon or magnetized plasma effect on an observable shadow and gravitational lensing of a Schwarzschild black hole
• Shadow, quasinormal modes and quasiperiodic oscillations of rotating Kaluza-Klein black holes
• Shadow and quasinormal modes of the Kerr-Newman-Kiselev-Letelier black hole
• Shadows and negative precession in non-Kerr spacetime
• The dynamics of generalized Palatini Theories of Gravity
• Emergent Gravity as the Eraser of Anomalous Gauge Boson Masses, and QFT-GR Concord
• Conformal Transformations in Metric-Affine Gravity and Ghosts

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• Apparent and emergent dark matter around a Schwarzschild black hole
• Constraints on Metric-Palatini Gravity from QPO Data
• Primordial Gravitational Waves in Generalized Palatini Gravity