From a locality-principle for new physics to image features of regular spinning black holes with disks

TL;DR

This paper develops a new class of regular black-hole models based on a locality principle, analyzes their observable features like shadows and photon rings, and generates simulated images to connect theoretical models with astrophysical observations.

Contribution

It introduces a novel family of regular black-hole spacetimes rooted in a locality principle and links their theoretical properties to observable image features.

Findings

Characteristic shadow features linked to the locality principle.

Photon rings as probes of new physics.

Simulated images show observable differences from classical black holes.

Abstract

Current observations present unprecedented opportunities to probe the true nature of black holes, which must harbor new physics beyond General Relativity to provide singularity-free descriptions. To test paradigms for this new physics, it is necessary to bridge the gap all the way from theoretical developments of new-physics models to phenomenological developments such as simulated images of black holes embedded in astrophysical disk environments. In this paper, we construct several steps along this bridge. We construct a novel family of regular black-hole spacetimes based on a locality principle which ties new physics to local curvature scales. We then characterize these spacetimes in terms of a complete set of curvature invariants and analyze the ergosphere and both the outer event as well as distinct Killing horizon. Our comprehensive study of the shadow shape at various spins and inclinations reveals characteristic image features linked to the locality principle. We also explore the photon rings as an additional probe of the new-physics effects. A simple analytical disk model enables us to generate simulated images of the regular spinning black hole and test whether the characteristic image-features are visible in the intensity map.