Upper bound on the GUP parameter using the black hole shadow

Abstract

An upper bound on the parameter that provides a generalized uncertainty principle (GUP) is obtained from the black hole shadow. With the aid of a recent constraint between regular black holes and the GUP parameter, it is indicated a relation between this parameter and the deviation from circularity of the black hole shadow. In the case of the recent announcement of the M87* results from the Event Horizon Telescope collaboration, a deviation from circularity $\lesssim 10\%$ imposes a GUP parameter ${\beta }_0<10^{90}$.

10 pages, 6 figures and 1 table. Version 2 with minor changes. Published in The European Physical Journal C