# Anomalies in Gravitational-Lensed Images Revealing Einstein Rings Modulated by Wavelike Dark Matter

**Authors:** Alfred Amruth, Tom Broadhurst, Jeremy Lim, Masamune Oguri, George F. Smoot, Jose M. Diego, Enoch Leung, Razieh Emami, Juno Li, Tzihong Chiueh, Hsi-Yu Schive, Michael C. H. Yeung, Sung Kei Li  
**arXiv:** [2304.09895](https://arxiv.org/abs/2304.09895)  
**Date:** 2023-04-19  
**Summary page:** https://www.summarizepaper.com/en/paper/2304.09895v1/

## Key points

- Dark Matter (DM) is a significant gap in our understanding of the universe.
- DM does not interact with light and interacts primarily with known matter through gravity.
- The leading candidates for DM are weakly interacting massive particles (WIMPs) or ultralight bosons (axions).
- WIMPs behave like discrete particles ($\varrho$DM), while quantum interference between DM axions is manifested as waves ($\psi$DM).
- Gravitational lensing leaves signatures in multiply-lensed images of background galaxies that reveal whether the foreground lensing galaxy inhabits a $\varrho$DM or $\psi$DM halo.
- $\varrho$DM lens models leave well-documented anomalies between the predicted and observed brightnesses and positions of multiply-lensed images, whereas $\psi$DM lens models correctly predict the level of anomalies left over by $\varrho$DM lens models.
- When subjected to tests for reproducing quadruply-lensed triplet images in the system HS 0810+2554, $\psi$DM was able to reproduce all aspects of this system whereas $\varrho$DM often failed.
- The growing success of $\psi$DM in reproducing astrophysical observations suggests new physics involving axions may be at play.
- This study provides new insights into the nature of DM and opens up new avenues for research into this elusive substance.

## Summary

The search for Dark Matter (DM) is one of the most important quests in physics, as it represents a significant gap in our understanding of the universe. DM does not interact with light and interacts primarily with known matter through gravity. The leading candidates for DM are weakly interacting massive particles (WIMPs) or ultralight bosons (axions), which have been postulated by competing theories to solve deficiencies in the Standard Model of particle physics. While WIMPs behave like discrete particles ($\varrho$DM), quantum interference between DM axions is manifested as waves ($\psi$DM). In a recent study, researchers from various institutions showed that gravitational lensing leaves signatures in multiply-lensed images of background galaxies that reveal whether the foreground lensing galaxy inhabits a $\varrho$DM or $\psi$DM halo. The team found that while $\varrho$DM lens models leave well-documented anomalies between the predicted and observed brightnesses and positions of multiply-lensed images, $\psi$DM lens models correctly predict the level of anomalies left over by $\varrho$DM lens models. Furthermore, when subjected to a battery of tests for reproducing the quadruply-lensed triplet images in the system HS 0810+2554, $\psi$DM was able to reproduce all aspects of this system whereas $\varrho$DM often failed. The growing success of $\psi$DM in reproducing astrophysical observations suggests new physics involving axions may be at play. This study provides new insights into the nature of DM and opens up new avenues for research into this elusive substance.