# New Classes of Spherically Symmetric, Inhomogeneous Cosmological Models

## TL;DR

This paper introduces two new classes of inhomogeneous, spherically symmetric solutions to Einstein-Maxwell-Perfect Fluid equations with a cosmological constant, expanding the landscape of cosmological models with potential topology changes and singularities.

## Contribution

The paper generalizes existing solutions by presenting new inhomogeneous, charged and uncharged models with cosmological constant, including cases with topology change and cosmological singularities.

## Key findings

- Existence of solutions with topology change between different FRW universes.
- Identification of spacelike surfaces with diverging Ricci scalar and pressure but finite density.
- Analysis of null geodesics and apparent horizons in the new solutions.

## Abstract

We present two classes of inhomogeneous, spherically symmetric solutions of the Einstein-Maxwell-Perfect Fluid field equations with cosmological constant generalizing the Vaidya-Shah solution. Some special limits of our solution reduce to the known inhomogeneous charged perfect fluid solutions of the Einstein field equations and under some other limits we obtain new charged and uncharged solutions with cosmological constant. Uncharged solutions in particular represent cosmological models where the universe may undergo a topology change and in between is a mixture of two different Friedmann-Robertson-Walker universes with different spatial curvatures. We show that there exist some spacelike surfaces where the Ricci scalar and pressure of the fluid diverge but the mass density of the fluid distribution remains finite. Such spacelike surfaces are known as (sudden) cosmological singularities. We study the behavior of our new solutions in their general form as the radial distance goes to zero and infinity. Finally, we briefly address the null geodesics and apparent horizons associated to the obtained solutions.