Constraints on a tidal charge of the supermassive black hole in M87* with the EHT observations in April 2017

Understand

More than two years ago the Event Horizon Telescope collaboration presented the first image reconstruction around the shadow for the supermassive black hole in M87*.

• It gives an opportunity to evaluate the shadow size.
• Recently, the Event Horizon Telescope collaboration constrained parameters ("charges") of spherical symmetrical metrics of black holes from an estimated allowed interval for shadow radius from observations of M87* in 2017.
• Earlier, analytical expressions for the shadow radius as a function of charge (including a tidal one) in the case of Reissner--Nordstr\"om metric have been obtained.