Parametric strong lensing model of the galaxy cluster Abell 2390 from Euclid and MUSE observations

¹ Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, I-20133 Milano, Italy
² INAF-IASF Milano, Via A. Corti 12, I-20133 Milano, Italy
³ INAF-OAS, Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Gobetti 93/3, I-40129 Bologna, Italy
⁴ Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Ferrara, Via Saragat 1, I-44122 Ferrara, Italy
⁵ Institute of Cosmology and Gravitation, University of Portsmouth, Burnaby Rd, Portsmouth PO1 3FX, UK
⁶ Dipartimento di Fisica e Astronomia, Universitá degli Studi di Padova, Vicolo dell’Osservatorio 3, I-35122 Padova, Italy
⁷ INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova, Italy
⁸ European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei München, Germany
⁹ Instituto de Fisica de Cantabria (IFCA), CSIC – Universidad de Cantabria, Avda. losAvda. los Castros, s/n, E-39005 Santander, Spain
¹⁰ Departamento de Fisica Moderna, Universidad de Cantabria, Avda. de los Castros s/n, E-39005 Santander, Spain
¹¹ INAF–Osservatorio Astronomico di Capodimonte, Via Moiariello 16, I-80131 Napoli, Italy
¹² INAF-OAT Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, I-34131 Trieste, Italy
¹³ Institut d’Astrophysique de Paris, UMR 7095, CNRS, and Sorbonne Université, 98 bis boulevard Arago, 75014 Paris, France
¹⁴ Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
¹⁵ Aix-Marseille Université, CNRS, CNES, LAM, Marseille, France
¹⁶ Department of Astronomy, University of Geneva, ch. d’Ecogia 16, 1290 Versoix, Switzerland
¹⁷ Instituto de Astrofísica de Canarias, Calle Vía Láctea s/n, 38204 San Cristóbal de La Laguna, Tenerife, Spain
¹⁸ Departamento de Astrofísica, Universidad de La Laguna, 38206 La Laguna, Tenerife, Spain
¹⁹ National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan

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Received: 14 July 2025
Accepted: 12 October 2025

Abstract

We present a new high-precision parametric strong lensing total mass reconstruction of the Euclid Early Release Observations (ERO) galaxy cluster Abell 2390 at redshift z = 0.231. We include in this analysis 35 multiple images from 13 background sources, of which 25 are spectroscopically confirmed thanks to observations from the Multi Unit Spectroscopic Explorer (MUSE), spanning a redshift range from z = 0.535 to z = 4.877. After fully re-analysing the MUSE spectroscopy, we combined it with archival spectroscopic catalogues, thus allowing us to select 65 secure cluster members. We further complemented this sample with 114 photometric member galaxies, identified within the Euclid VIS and NISP imaging down to magnitude H_E = 23. We also measured the stellar velocity dispersions for 22 cluster members in order to calibrate the Faber–Jackson relation and hence the scaling relations for the sub-halo mass components. We tested and compared 11 total mass parametrisations of the galaxy cluster with increasing complexity. To do so, we employed the new parametric strong lensing modelling code Gravity.jl. Our best-fit total mass parametrisation is characterised by a single large-scale halo, 179 sub-halo components, and an external shear term. The reference model yields a mean scatter between the model-predicted and observed positions of the multiple images of 0.​​″32. We were able to quantify the systematics arising from our modelling choices by taking advantage of all the different explored total mass parametrisations. When comparing our results with those from other lensing studies, we noticed an overall agreement in the reconstructed cluster total mass profile in the outermost strong lensing regime. The discrepancy in the innermost region of the cluster (a few kiloparsecs from the brightest cluster galaxy, where few or no strong lensing features are observed) could possibly be ascribed to the different data and modelling choices.