Working Paper Article Version 1 This version is not peer-reviewed

# Brightest Point in Accretion Disk and Black Hole Spin: Implication to the Image of Black Hole M87*

Version 1 : Received: 17 June 2019 / Approved: 18 June 2019 / Online: 18 June 2019 (10:31:12 CEST)

A peer-reviewed article of this Preprint also exists.

Dokuchaev, V.I.; Nazarova, N.O. The Brightest Point in Accretion Disk and Black Hole Spin: Implication to the Image of Black Hole M87*. Universe 2019, 5, 183. Dokuchaev, V.I.; Nazarova, N.O. The Brightest Point in Accretion Disk and Black Hole Spin: Implication to the Image of Black Hole M87*. Universe 2019, 5, 183.

Journal reference: Universe 2019, 5, 183
DOI: 10.3390/universe5080183

## Abstract

A dark region and a bright part of accretion disk are viewed on the first image of the supermassive black hole in the galaxy M87 obtained by the Event Horizon Telescope. We demonstrate that a viewed dark region is a silhouette of the black hole event horizon, while the outline (contour) of this silhouette is an equator of the event horizon globe. A dark silhouette of the black hole event horizon is placed within the expected position of the black hole shadow, which is not revealed on the first image. We calculate numerically a relation between the viewed position of the black hole silhouette and the brightest point in a thin accretion disk in dependence of the black hole spin. A spin of the supermassive black hole in the galaxy M87, derived from this relation, is $a=0.75\pm0.15$.

## Subject Areas

General Relativity, gravity, black hole, black hole shadow

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