Shadows of Colliding Black Holes

TL;DR

This paper models the shadows of colliding black holes using an exact cosmological solution, revealing unique eyebrowlike features that could help identify black hole mergers.

Contribution

It introduces a novel application of the Kastor-Traschen solution to black hole shadow analysis, highlighting observable features during mergers.

Findings

Black hole shadows exhibit eyebrowlike structures during collision.

These features can serve as observational probes for black hole mergers.

The study provides a theoretical framework for interpreting black hole shadow observations.

Abstract

We compute the shadows of colliding black holes using the Kastor-Traschen cosmological multiblack hole solution that is an exact solution describing the collision of maximally charged black holes with a positive cosmological constant. We find that in addition to the shadow of each black hole, an eyebrowlike structure appears as the black holes come close to each other. These features can be used as probes to find the multiblack hole system at the final stage of its merger process.