Exotic Image Formation in Strong Gravitational Lensing by Clusters of Galaxies -- III: Statistics with HUDF

TL;DR

This paper analyzes the statistics of exotic image formations near point singularities in strongly lensed images of the HUDF by galaxy clusters, revealing that such formations have significantly shorter time delays than typical five-image lenses.

Contribution

It provides a statistical analysis of exotic gravitational lensing images near singularities using simulated HUDF data, extending previous approaches.

Findings

Exotic image formations are consistent with earlier results.

Time delays in exotic images are an order of magnitude smaller.

Study uses multiple realizations with cluster translations and rotations.

Abstract

We study the image formation near point singularities (swallowtail and umbilics) in the simulated strongly lensed images of Hubble Ultra Deep Field (HUDF) by the Hubble Frontier Fields (HFF) clusters. In this work, we only consider nearly half of the brightest (a total of 5271) sources in the HUDF region. For every HFF cluster, we constructed 11 realizations of strongly lensed HUDF with an arbitrary translation of the cluster centre within the central region of HUDF and an arbitrary rotation. In each of these realizations, we visually identify the characteristic/exotic image formation corresponding to the different point singularities. We find that our current results are consistent with our earlier results based on different approaches. We also study time delay in these exotic image formations and compare it with typical five-image geometries. We find that the typical time delay in exotic image formations is an order of magnitude smaller than the typical time delay in a generic five-image geometry.