A high-resolution view of the source-plane magnification near cluster caustics in wave dark matter models

TL;DR

This paper provides high-resolution images of wave dark matter caustics near cluster lens critical curves, highlighting unique magnification features that can distinguish wave dark matter from cold dark matter through specific lensing signatures.

Contribution

It offers the highest resolution images of wave dark matter caustics and identifies distinctive lensing features that differentiate it from cold dark matter models.

Findings

Wave dark matter caustics exhibit unique demagnified counterimages.

Substructure in CDM cannot produce similar demagnified images.

Highly magnified small sources can discriminate between wave dark matter and CDM.

Abstract

We present the highest resolution images to date of caustics formed by wave dark matter ($\psi$DM) fluctuations near the critical curves of cluster gravitational lenses. We describe the basic magnification features of $\psi$DM in the source plane at high macromodel magnification and discuss specific differences between the $\psi$DM and standard cold dark matter (CDM) models. The unique generation of demagnified counterimages formed outside the Einstein radius for $\psi$DM is highlighted. Substructure in CDM cannot generate such demagnified images of positive parity, thus providing a definitive way to distinguish $\psi$DM from CDM. Highly magnified background sources with sizes $r\approx 1pc$, or approximately a factor of ten smaller than the expected de Broglie wavelength of $\psi$DM, offer the best possibility of discriminating between $\psi$DM and CDM. These include objects such as very compact stellar clusters at high redshift that JWST is finding in abundance.