Causal structure of black holes immersed in a Chaplygin-like dark fluid environment: Horizons and singularities

TL;DR

This paper analyzes how a Chaplygin-like dark fluid influences the causal structure, horizons, and singularities of spherically symmetric black holes, revealing stronger curvature effects and modified extremal conditions.

Contribution

It introduces the impact of a Chaplygin-like dark fluid on black hole horizons, curvature, and extremal parameters, highlighting differences from classical Reissner-Nordstrom geometries.

Findings

Spacetime curvature is significantly stronger than in Reissner-Nordstrom-de Sitter geometry.

The maximum charge for horizons is approximately 0.556219 times the mass, smaller than in classical cases.

Derived a critical condition for the dark fluid parameter B, constraining multi-horizon solutions.

Abstract

In the present work, we study the causal structure of spherically symmetric black holes immersed in a Chaplygin-like dark fluid, emphasizing the impact of the fluid parameters on curvature and horizon formation. We show that the spacetime curvature is significantly stronger than in its similar counterpart, the Reissner-Nordstrom-de Sitter geometry with the same mass and charge, leading to modifications of the internal causal structure. For the presence of horizons the Chaplygin black hole possesses an upper bound $Q \approx 0.556219 M$, which is much smaller than that for Reissner-Nordstrom spacetime $Q_{\text{critical}} = M$ or of the Reissner-Nordstrom-de Sitter case $Q_{\text{critical}} = 3M/(2\sqrt{2})$, indicating that the black holes immersed in a Chaplygin-like dark fluid reach the extremal regime more easily. We derive a second critical condition for the Chaplygin cosmological parameter $B$, $B_c Q_c^4 = 4/3^9$, setting an upper bound on $B$ for a multi-horizon solution.