Constraining the Generalized Uncertainty Principle Through Black Hole Shadow and Quasiperiodic Oscillations

TL;DR

This study investigates how the Generalized Uncertainty Principle (GUP) influences black hole shadows and quasinormal modes, using observational data to constrain the GUP parameter and exploring potential quantum gravity effects.

Contribution

It provides the first constraints on the GUP parameter from black hole shadow observations and connects GUP effects with quasinormal mode frequencies.

Findings

GUP increases the shadow radius of Kerr black holes.

Upper limit of GUP parameter constrained to 10^{95} from EHT data.

GUP-modified black holes fit observed microquasar frequencies within 10^{77} bounds.

Abstract

In this paper we study the effect of the Generalized Uncertainty Principle (GUP) on the shadow of GUP-modified Kerr black hole and the correspondence between the shadow radius and the real part of the quasinormal modes (QNMs). We find that the shadow curvature radius of the GUP-modfied Kerr black hole is bigger compared to the Kerr vacuum solution and increases linearly monotonically with the increase of the GUP parameter. We then investigate the characteristic points of intrinsic curvature of the shadow from a topological point of view to calculate the the angular size for these curvature radii of the shadow. To this end, we have used the EHT data for the M87* black hole to constrain the upper limits of the GUP parameter red and our result is $\beta<10^{95}$. Finally, we have explored the connection between the shadow radius and the scalar/electromagnetic/gravitational QNMs. The GUP-modified Kerr black hole is also used to provide perfect curve fitting of the particle oscillation upper and lower frequencies to the observed frequencies for three microquasars and to restrict the values of the correction parameter in the metric of the modified black hole to very reasonable bound $\beta<10^{77}$.