Lensing effects in inhomogeneous cosmological models

TL;DR

This paper investigates gravitational lensing effects in inhomogeneous cosmological models, specifically LTB and Swiss-cheese models, to assess their viability in explaining cosmic acceleration and their observable differences from standard models.

Contribution

It analyzes lensing signatures in LTB and Swiss-cheese models, revealing differences in shear, convergence, and arc formation compared to homogeneous cosmologies.

Findings

Shear vanishes at the origin in LTB models, similar to FRW.

Convergence differs in LTB models, affecting observable effects.

Swiss-cheese models show distinct arc formation behavior.

Abstract

Concepts developed in the gravitational lensing techniques such as shear, convergence, tangential and radial arcs maybe used to see how tenable inhomogeneous models proposed to explain the acceleration of the universe models are. We study the widely discussed LTB cosmological models. It turns out that for the observer sitting at origin of a global LTB solution the shear vanishes as in the FRW models, while the value of convergence is different which may lead to observable cosmological effects. We also consider Swiss-cheese models proposed recently based on LTB with an observer sitting in the FRW part. It turns out that they have different behavior as far as the formation of radial and tangential arcs are concerned.