A shot in the dark: searching for dark substructures in the RX J0437+00 galaxy cluster

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Lagattuta, David J., Jauzac, Mathilde, Doppel, Jessica E., Mahler, Guillaume, Niemiec, Anna
Format: Preprint
Published: 2026
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866911393289076736
author Lagattuta, David J.
Jauzac, Mathilde
Doppel, Jessica E.
Mahler, Guillaume
Niemiec, Anna
author_facet Lagattuta, David J.
Jauzac, Mathilde
Doppel, Jessica E.
Mahler, Guillaume
Niemiec, Anna
contents Obtaining a census of dark matter structures at low mass ($\leq 10^9 M_\odot$) can provide strong constraints on the nature of dark matter, though identifying such structures remains difficult. In this work, we study the galaxy cluster RX J0437.1+0043, taking advantage of its powerful "exotic" Hyperbolic-Umbilic (HU) lensing configuration to search for substructure candidates. Using a combination of high resolution imaging, IFU spectroscopy, and gravitational lensing modelling, we report on a tentative detection of a dark matter subhalo ($m_{\rm halo} = 2.25 \pm 0.94 \times 10^9 M_\odot$) near the vicinity of one of the largest HU images. We stress that this result is still preliminary and that deeper data and more advanced modelling techniques are needed to ultimately confirm this detection. Nevertheless, this work outlines the first steps towards understanding subhalo properties in dense cluster environments, developing HU cluster lenses as a potential new tool for investigating dark matter.
format Preprint
id arxiv_https___arxiv_org_abs_2601_16260
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A shot in the dark: searching for dark substructures in the RX J0437+00 galaxy cluster
Lagattuta, David J.
Jauzac, Mathilde
Doppel, Jessica E.
Mahler, Guillaume
Niemiec, Anna
Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
Obtaining a census of dark matter structures at low mass ($\leq 10^9 M_\odot$) can provide strong constraints on the nature of dark matter, though identifying such structures remains difficult. In this work, we study the galaxy cluster RX J0437.1+0043, taking advantage of its powerful "exotic" Hyperbolic-Umbilic (HU) lensing configuration to search for substructure candidates. Using a combination of high resolution imaging, IFU spectroscopy, and gravitational lensing modelling, we report on a tentative detection of a dark matter subhalo ($m_{\rm halo} = 2.25 \pm 0.94 \times 10^9 M_\odot$) near the vicinity of one of the largest HU images. We stress that this result is still preliminary and that deeper data and more advanced modelling techniques are needed to ultimately confirm this detection. Nevertheless, this work outlines the first steps towards understanding subhalo properties in dense cluster environments, developing HU cluster lenses as a potential new tool for investigating dark matter.
title A shot in the dark: searching for dark substructures in the RX J0437+00 galaxy cluster
topic Cosmology and Nongalactic Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2601.16260