Euclid: Galaxy cluster detection through the weak lensing effect - algorithm assessment and selection
Abstract
Weak gravitational lensing offers a powerful way to detect galaxy clusters by directly tracing their total matter content. Its effectiveness increases with the density of background galaxies, a requirement that is now being met by the high sensitivity and wide coverage of current large-area surveys. A prime example is the Euclid telescope, which will map approximately 14 000 deg2 of the sky, measuring the shapes of billions of galaxies and opening a meaningful window for detecting galaxy clusters uniquely through their weak lensing signal. We present the results of nine galaxy cluster detection algorithms in a blind challenge, using 1200 deg2 of Euclid-like weak lensing observations from the DEMNUni-Cov simulations. The performance of these methods was assessed by matching their detections to known synthetic clusters with signal-to-noise ratios greater than 2, satisfying the z-M selection cut, and adopting two different matching procedures. The purpose of the challenge was to identify and improve strategies for galaxy cluster detection via weak lensing for the upcoming Euclid data releases. We pre-selected four methods based on their individual performance and complementarity. Each pre-selected method adopts a distinct approach: AMICO-WL uses an optimal filtering technique, DoG employs Gaussian filtering, O21 relies on aperture-mass filtering, and W234 applies multi-scale wavelet filtering. Together, the results of these methods can be merged to enhance the processing of Euclid data. Individually, these algorithms reach approximately 10% completeness for a mean purity of 90%, while their combination leads to roughly a two-fold improvement in overall performance, exceeding 70% completeness for low-redshift, high-mass clusters. When extrapolating the results of this work to Euclid Data Release 1, we expect to detect approximately 2500 galaxy clusters via weak gravitational lensing.
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BibTeX
@misc{manjongarcia2026euclid,
title = {{Euclid: Galaxy cluster detection through the weak lensing effect - algorithm assessment and selection}},
author = {A Manjón-García and G Leroy and S Pires and J.M Diego and C Giocoli and L Trobbiani and A Díaz-Sánchez and M Maturi and M Oguri and G Panebianco and G.W Pratt and S Andreon and L Moscardini and M Sereno and C Carbone and A.M.C Le Brun and M Lieu and L Chappuis and B Altieri and T Castro and M Douspis and D Eckert and S Farrens and R Gavazzi and A.H Gonzalez and L Ingoglia and E Jullo and S Maurogordato and J.-B Melin and N Okabe and F Pacaud and M Radovich and Z Sakr and Laura Salvati and B Sartoris and S.A Stanford and J.E Taylor and J Weller and C Wood and C Baccigalupi and M Baldi and S Bardelli and P Battaglia and A Biviano and E Branchini and M Brescia and S Camera and V Capobianco and V.F Cardone and J Carretero and M Castellano and G Castignani and S Cavuoti and A Cimatti and C Colodro-Conde and G Congedo and L Conversi and Y Copin and F Courbin and H.M Courtois},
howpublished = {HAL},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.20571},
eprint = {2609.20571},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05763283v1},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Euclid: Galaxy cluster detection through the weak lensing effect - algorithm assessment and selection
AU - A Manjón-García
AU - G Leroy
AU - S Pires
AU - J.M Diego
AU - C Giocoli
AU - L Trobbiani
AU - A Díaz-Sánchez
AU - M Maturi
AU - M Oguri
AU - G Panebianco
AU - G.W Pratt
AU - S Andreon
AU - L Moscardini
AU - M Sereno
AU - C Carbone
AU - A.M.C Le Brun
AU - M Lieu
AU - L Chappuis
AU - B Altieri
AU - T Castro
AU - M Douspis
AU - D Eckert
AU - S Farrens
AU - R Gavazzi
AU - A.H Gonzalez
AU - L Ingoglia
AU - E Jullo
AU - S Maurogordato
AU - J.-B Melin
AU - N Okabe
AU - F Pacaud
AU - M Radovich
AU - Z Sakr
AU - Laura Salvati
AU - B Sartoris
AU - S.A Stanford
AU - J.E Taylor
AU - J Weller
AU - C Wood
AU - C Baccigalupi
AU - M Baldi
AU - S Bardelli
AU - P Battaglia
AU - A Biviano
AU - E Branchini
AU - M Brescia
AU - S Camera
AU - V Capobianco
AU - V.F Cardone
AU - J Carretero
AU - M Castellano
AU - G Castignani
AU - S Cavuoti
AU - A Cimatti
AU - C Colodro-Conde
AU - G Congedo
AU - L Conversi
AU - Y Copin
AU - F Courbin
AU - H.M Courtois
PY - 2026
DA - 2026/09/17
PB - HAL
DO - 10.48550/arxiv.2609.20571
UR - https://hal.science/hal-05763283v1
AB - Weak gravitational lensing offers a powerful way to detect galaxy clusters by directly tracing their total matter content. Its effectiveness increases with the density of background galaxies, a requirement that is now being met by the high sensitivity and wide coverage of current large-area surveys. A prime example is the Euclid telescope, which will map approximately 14 000 deg2 of the sky, measuring the shapes of billions of galaxies and opening a meaningful window for detecting galaxy clusters uniquely through their weak lensing signal. We present the results of nine galaxy cluster detection algorithms in a blind challenge, using 1200 deg2 of Euclid-like weak lensing observations from the DEMNUni-Cov simulations. The performance of these methods was assessed by matching their detections to known synthetic clusters with signal-to-noise ratios greater than 2, satisfying the z-M selection cut, and adopting two different matching procedures. The purpose of the challenge was to identify and improve strategies for galaxy cluster detection via weak lensing for the upcoming Euclid data releases. We pre-selected four methods based on their individual performance and complementarity. Each pre-selected method adopts a distinct approach: AMICO-WL uses an optimal filtering technique, DoG employs Gaussian filtering, O21 relies on aperture-mass filtering, and W234 applies multi-scale wavelet filtering. Together, the results of these methods can be merged to enhance the processing of Euclid data. Individually, these algorithms reach approximately 10% completeness for a mean purity of 90%, while their combination leads to roughly a two-fold improvement in overall performance, exceeding 70% completeness for low-redshift, high-mass clusters. When extrapolating the results of this work to Euclid Data Release 1, we expect to detect approximately 2500 galaxy clusters via weak gravitational lensing.
ER -