Exotic Image Formation in Strong Gravitational Lensing by Clusters of Galaxies -- II: Uncertainties

TL;DR

This paper investigates how uncertainties in galaxy cluster mass models affect the predicted singularity maps and observable lensing features, providing estimates for JWST observations based on simulated and real data.

Contribution

It analyzes the impact of mass model uncertainties on singularity maps and predicts the number of observable three-image arcs with JWST.

Findings

At least 20-30 tangential three-image arcs expected in JWST observations.

At least 5-10 radial three-image arcs expected in JWST observations.

Best-fit mass models yield the simplest singularity maps and lower limits on lensing features.

Abstract

Due to the finite amount of observational data, the best-fit parameters corresponding to the reconstructed cluster mass have uncertainties. In turn, these uncertainties affect the inferences made from these mass models. Following our earlier work, we have studied the effect of such uncertainties on the singularity maps in simulated and actual galaxy clusters. The mass models for both simulated and real clusters have been constructed using grale. The final best-fit mass models created using grale give the simplest singularity maps and a lower limit on the number of point singularities that a lens has to offer. The simple nature of these singularity maps also puts a lower limit on the number of three image (tangential and radial) arcs that a cluster lens has. Hence, we estimate the number of galaxy sources giving rise to the three image arcs, which can be observed with the James Webb Space Telescope (JWST). We find that we expect to observe at least 20-30 tangential and 5-10 radial three-image arcs in the Hubble Frontier Fields cluster lenses with the JWST.