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Main Authors: Kim, Soojin, Hwang, Ho Seong, Jeffrey, Niall
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2509.25836
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author Kim, Soojin
Hwang, Ho Seong
Jeffrey, Niall
author_facet Kim, Soojin
Hwang, Ho Seong
Jeffrey, Niall
contents We present the result of a comparison between the dark matter distribution inferred from weak gravitational lensing and the observed galaxy distribution to identify dark structures with a high dark matter-to-galaxy density ratio. To do this, we use weak-lensing convergence maps from the Dark Energy Survey Year 3 data, and construct corresponding galaxy convergence maps at $z\lesssim1.0$ , representing projected galaxy number density fluctuations weighted by lensing efficiency. The two maps show overall agreement. However, we could identify 22 regions where the dark matter density exhibits an excess compared to the galaxy density. After carefully examining the survey depths and proximity to survey boundaries, we select the seven most probable candidates for dark structures. This sample provides valuable test beds for further investigations into dark matter mapping. Moreover, our method will be very useful for future studies of dark structures as large-scale weak-lensing surveys become available, such as the Euclid mission, the Vera C. Rubin Observatory's Legacy Survey of Space and Time, and the Nancy Grace Roman Space Telescope.
format Preprint
id arxiv_https___arxiv_org_abs_2509_25836
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Searching for Dark Structures: A Comparison of Weak-lensing Convergence Maps and Lensing-weighted Galaxy Density Maps
Kim, Soojin
Hwang, Ho Seong
Jeffrey, Niall
Cosmology and Nongalactic Astrophysics
Instrumentation and Methods for Astrophysics
We present the result of a comparison between the dark matter distribution inferred from weak gravitational lensing and the observed galaxy distribution to identify dark structures with a high dark matter-to-galaxy density ratio. To do this, we use weak-lensing convergence maps from the Dark Energy Survey Year 3 data, and construct corresponding galaxy convergence maps at $z\lesssim1.0$ , representing projected galaxy number density fluctuations weighted by lensing efficiency. The two maps show overall agreement. However, we could identify 22 regions where the dark matter density exhibits an excess compared to the galaxy density. After carefully examining the survey depths and proximity to survey boundaries, we select the seven most probable candidates for dark structures. This sample provides valuable test beds for further investigations into dark matter mapping. Moreover, our method will be very useful for future studies of dark structures as large-scale weak-lensing surveys become available, such as the Euclid mission, the Vera C. Rubin Observatory's Legacy Survey of Space and Time, and the Nancy Grace Roman Space Telescope.
title Searching for Dark Structures: A Comparison of Weak-lensing Convergence Maps and Lensing-weighted Galaxy Density Maps
topic Cosmology and Nongalactic Astrophysics
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2509.25836