Microlensing due to both gravitation and refraction as a further probe of universe evolution

TL;DR

This paper explores microlensing effects caused by both gravity and refraction in cosmological sources, finding refraction effects are generally negligible but could be useful with future high-resolution observations.

Contribution

It provides detailed predictions of refraction-induced microlensing and compares it with gravitational effects, highlighting potential for future observational probes.

Findings

Refraction effects are mostly negligible compared to gravitational lensing.

Refraction could be detected with future high-resolution telescopes.

Refraction effects can serve as additional tools for universe evolution studies.

Abstract

Microlensings events are predicted for the light coming from cosmological sources. In addition to the microlensing due to gravitation lensing, microlensing produced also by refraction of light due to either ionized, or not, gas clouds can be considered. A detailed prediction is here given assuming that the ray of light coming from the distant source traverses a gas cloud with a King's density profile for various possible environments. We conclude that the additional deviation due to relativistic refraction is in most cases negligible compared to the gravitational deviation. Deviation due to refraction can anyway become an interesting analysis tool for future facility with great resolving power and the effects can be singled out with dedicated surveys.