Event horizon silhouette: implications to supermassive black holes M87* and SgrA*

Abstract

We demonstrate that a dark silhouette of the black hole illuminated by a thin accretion disk and seen by a distant observer is, in fact, a silhouette of the event horizon hemisphere. The boundary of this silhouette is a contour of the event horizon equatorial circle if a thin accretion disk is placed in the black hole equatorial plane. A luminous matter plunging into black hole from different directions provides the observational opportunity for recovering a total silhouette of the invisible event horizon globe. The event horizon silhouette is projected on the celestial sphere within a position of the black hole shadow. A relative position of brightest point in the accretion disk with respect to the position of event horizon silhouette in the image of black hole in the galaxy M87, observed by the Event Horizon Telescope, corresponds to a rather high value of the black hole spin, $a\simeq 0.75$.

17 pages, 12 figures, references added, accepted to Gen. Rel. Gravit

References in corpus (7)

• The old nuclear star cluster in the Milky Way: dynamics, mass, statistical parallax, and black hole mass
• Gravitational Lensing by Spinning Black Holes in Astrophysics, and in the Movie Interstellar
• Testing General Relativity with Accretion-Flow Imaging of Sgr A*
• Test of Einstein equivalence principle near the Galactic center supermassive black hole
• Quantifying Intrinsic Variability of Sagittarius A* using Closure Phase Measurements of the Event Horizon Telescope
• Seeing the unseeable
• Tests of gravity theories with Galactic Center observations

Cited by in corpus (4)

• Observational signature of a near-extremal Kerr-Sen black hole in the heterotic string theory
• Spin oscillations of neutrinos scattered off a rotating black hole
• Spins of supermassive black holes M87* and SgrA* revealed from the size of dark spots in Event Horizon Telescope Images
• Black Hole Shadow Observations with Space-Ground Interferometers