Shadows of quintessence black holes: spherical accretion, photon trajectories, and geodesic observers

Abstract

The presence of a quintessence-like field can influence the black hole shadow through three primary mechanisms: the dynamics of accretion flows, the trajectories of photons, and the motion of observers. Unlike standard shadow analyses that assume a static observer at spatial infinity, the non-asymptotically flat nature of quintessence-corrected spacetimes motivates the consideration of freely falling (geodesic) observers. Using a perturbative approach, we derive analytical expressions for the event-horizon location, photon-sphere radius, innermost stable circular orbit, and critical impact parameter. We compute the observed intensity profiles for both static and infalling spherical accretion flows. We find that, although the photon-sphere radius and the critical impact parameter are invariant properties of the spacetime, the apparent angular size of the shadow depends sensitively on the observer's motion and location. Freely infalling observers systematically measure smaller angular radii than static observers at the same radius, whereas freely outgoing observers measure larger ones, in agreement with relativistic aberration. In contrast to the Schwarzschild case, the impact parameter alone is insufficient to characterize the observed angular structure in non-asymptotically flat spacetimes. Applying our results to the Event Horizon Telescope observation of M87${}^{\ast }$, we show that more negative equations of state lead to stronger constraints on the quintessence parameter, largely independent of the observer prescription. Our analysis highlights the importance of carefully specifying the observer in shadow studies of non-asymptotically flat black-hole spacetimes.

15 pages, 11 figures, 1 table

References in corpus (19)

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
• First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole
• 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
• The Shadow of a Spherically Accreting Black Hole
• Influence of quintessence dark energy on the shadow of black hole
• Quasinormal modes of gravitational perturbation around a Schwarzschild black hole surrounded by quintessence
• Shadows and gravitational weak lensing by the Schwarzschild black hole in the string cloud background with quintessential field
• Deflection Angle and Shadow Behaviors of Quintessential Black Holes in arbitrary Dimensions
• Shadow and quasinormal modes of the Kerr-Newman-Kiselev-Letelier black hole
• Dynamical features and shadows of quantum Schwarzschild black hole in effective field theories of gravity
• Black Hole Images as Tests of General Relativity: Effects of Plasma Physics
• The effect of scalar hair on the charged black hole with the images from accretions disk
• Shadows of magnetically charged rotating black holes surrounded by quintessence
• Shadows and rings of a de Sitter-Schwarzschild black hole
• Quantum-corrected Schwarzschild AdS black hole surrounded by quintessence: Thermodynamics and Shadows
• Illuminating Black Hole Shadow with Dark Matter Annihilation
• Exploring the role of accretion disk geometry in shaping black hole shadows

Cited by in corpus (1)

• Energy conditions in static, spherically symmetric spacetimes and effective geometries