The observer-dependent shadow of the Kerr black hole

Abstract

Motivated by inclination of the Earth's orbit that is not located at galactic plane for observing the shadow of Sgr A*, we consider the black hole shadow for arbitrary inclinations and different velocities of observers. A surprising finding of the study is that rotation axis of a black hole might not be extracted from its shadow, since the ways of the shadow getting distorted depend not only on the spin of the black hole, but also velocities of observers. Namely, appearance of the shadow could be rotated by an angle in observers' celestial sphere due to the observer in motion. In order to further confirm this result, a formalism is presented for calculating the shadow in terms of the velocity perturbations. Besides, we also consider the Earth's orbit for the shadow of Sgr A* by making use of this formalism.

v2: 28 pages, 19 figures, 2 tables, minor revisions

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Cited by in corpus (10)

• Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A${}^{\ast }$
• Photon regions, shadow observables and constraints from M87* of a charged rotating black hole
• Shadows of rotating black holes in plasma environments with aberration effects
• Shadows in dyonic Kerr-Sen black holes
• Determination of the spin parameter and the inclination angle by the relativistic images in black hole image
• The ring-shaped shadow of rotating naked singularity with a complete photon sphere
• Observational signatures from higher-order images of moving hotspots in accretion disks
• The surface geometry and shadow of a Schwarzschild black hole with halo
• Aberration effect on lower-order images of thin accretion disk in the astrometric approach
• Investigating non-Keplerian motion in flare events with astrometric data