Shadows of naked singularity in Brans-Dicke gravity

Abstract

We investigate the observational features of exact vacuum solutions in Brans-Dicke (BD) gravity, focusing on their implications for black hole shadow imaging. Motivated by the Event Horizon Telescope (EHT) observations, we revisit a class of BD solutions that exhibit a naked singularity. These solutions, despite lacking a conventional event horizon, exhibit photon spheres and produce shadow-like features. We analyze null geodesics and perform ray-tracing simulations under a simplified, optically thin accretion disk model to generate synthetic images. Our results show that BD naked singularities can cast shadows smaller than those of Schwarzschild black holes of equivalent mass. We identify the parameter space $-3/2<\omega <0$ as physically viable, ensuring attractive gravity and the absence of ghost fields. These findings suggest that BD naked singularities are possible candidates for compact astrophysical objects.

arXiv commentAccepted for publication in EPJC. 7 pages, 3 figures. It contains some additional comments and references

References in corpus (39)

• Observation of Gravitational Waves from a Binary Black Hole Merger
• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• The Confrontation between General Relativity and Experiment
• First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
• Tests of general relativity with GW150914
• The String Dilaton and a Least Coupling Principle
• High Proper Motion Stars in the Vicinity of Sgr A*: Evidence for a Supermassive Black Hole at the Center of Our Galaxy
• Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A${}^{\ast }$
• Black Hole Shadows, Photon Rings, and Lensing Rings
• Calculating black hole shadows: Review of analytical studies
• The geometry of photon surfaces
• Detection of the Schwarzschild precession in the orbit of the star S2 near the Galactic centre massive black hole
• GRMHD Simulations of Magnetized Advection Dominated Accretion on a Non-Spinning Black Hole: Role of Outflows
• An Update on Monitoring Stellar Orbits in the Galactic Center
• The Black-Hole Mass in M87 from Gemini/NIFS Adaptive Optics Observations
• Violations of the equivalence principle in a dilaton-runaway scenario
• Dressing a black hole with a time-dependent Galileon
• General relativistic magnetohydrodynamical simulations of the jet in M87
• The M87 Black Hole Mass from Gas-dynamical Models of Space Telescope Imaging Spectrograph Observations
• Shadows of spherically symmetric black holes and naked singularities
• The Shape of the Black Hole Photon Ring: A Precise Test of Strong-Field General Relativity
• Brans-Dicke wormholes in the Jordan and Einstein frames
• Key Science Goals for the Next-Generation Event Horizon Telescope
• Brans wormholes
• Shadows and photon rings of regular black holes and geonic horizonless compact objects
• Images and photon ring signatures of thick disks around black holes
• Shadow of a Naked Singularity without Photon Sphere
• The Vainshtein Mechanism in the Cosmic Web
• Shadow of a naked singularity
• Palatini $f(R)$ gravity in the solar system: post-Newtonian equations of motion and complete PPN parameters
• Gravitational lensing by a photon sphere in a Reissner-Nordström naked singularity spacetime in strong deflection limits
• The Parametrized Post-Newtonian-Vainshteinian Formalism
• Revisiting the Brans solutions of scalar-tensor gravity
• Wormholes in vacuum Brans-Dicke theory
• The GRAVITY+ Project: Towards All-sky, Faint-Science, High-Contrast Near-Infrared Interferometry at the VLTI
• The jet and resolved features of the central supermassive black hole of M 87 observed with EHT
• Approximate Black Holes for Numerical Relativity
• An independent hybrid imaging of Sgr A* from the data in EHT 2017 observations
• A detailed first-order post-Newtonian analysis of massive Brans-Dicke theories: numerical constraints and the $\beta$ parameter meaning

Cited by in corpus (3)

• Energy conditions in static, spherically symmetric spacetimes and effective geometries
• Optical appearance of regularized compact objects without an exterior photon sphere
• Images and photon regions of continuous photon sphere spacetime