# Exact cosmological black hole solutions in Scalar Tensor Vector Gravity

## TL;DR

This paper presents the first exact black hole solution in Scalar-Tensor-Vector Gravity embedded in an expanding universe, analyzing its horizons and singularities to understand its physical implications and constrain the theory's parameters.

## Contribution

It provides the first exact solution of a cosmological black hole in Scalar-Tensor-Vector Gravity and explores its properties and implications.

## Key findings

- Solution describes black holes, inhomogeneities, or naked singularities depending on parameters.
- Analysis of horizons and singularities informs constraints on theory parameters.
- Comparison with McVittie spacetime highlights differences in alternative gravity theories.

## Abstract

We find an exact solution of Scalar-Tensor-Vector Gravity field equations that represents a black hole embedded in an expanding universe. This is the first solution of the kind found in the theory. We analyze the properties of the apparent horizons as well as the essential singularities of the metric, and compare it with the McVittie spacetime of General Relativity. Depending on the cosmological model adopted and the value of the free parameter $\alpha $ of the theory, the solution describes a cosmological black hole, an inhomogeneity in an expanding universe, or a naked singularity. We use the latter result to set further constraints on the free parameters of the theory.