Euclid: Quick Data Release (Q1) ─ Watching ICM-selected galaxy clusters with Euclid eyes: Prospects of Euclid data in the context of large SZE- and X-ray-based surveys

June 2026 • 2026A&A...711A..41K

Authors • Klein, M. • George, K. • Mohr, J. J. • Altieri, B. • Amendola, L. • Andreon, S. • Auricchio, N. • Baccigalupi, C. • Baldi, M. • Balestra, A. • Bardelli, S. • Biviano, A. • Branchini, E. • Brescia, M. • Camera, S. • Cañas-Herrera, G. • Capobianco, V. • Carbone, C. • Carretero, J. • Casas, S. • Castellano, M. • Castignani, G. • Cavuoti, S. • Chambers, K. C. • Cimatti, A. • Colodro-Conde, C. • Congedo, G. • Conversi, L. • Copin, Y. • Courbin, F. • Courtois, H. M. • Cropper, M. • Da Silva, A. • Degaudenzi, H. • De Lucia, G. • Dolding, C. • Dole, H. • Dubath, F. • Ducret, F. • Dupac, X. • Dusini, S. • Farina, M. • Farinelli, R. • Faustini, F. • Ferriol, S. • Finelli, F. • Frailis, M. • Franceschi, E. • Fumana, M. • Galeotta, S. • Gillis, B. • Giocoli, C. • Gracia-Carpio, J. • Grazian, A. • Grupp, F. • Haugan, S. V. H. • Holmes, W. • Hook, I. M. • Hormuth, F. • Hornstrup, A. • Jahnke, K. • Jhabvala, M. • Keihänen, E. • Kermiche, S. • Kubik, B. • Kümmel, M. • Kunz, M. • Kurki-Suonio, H. • Le Brun, A. M. C. • Le Mignant, D. • Ligori, S. • Lilje, P. B. • Lindholm, V. • Lloro, I. • Mainetti, G. • Maino, D. • Maiorano, E. • Mansutti, O. • Marggraf, O. • Martinelli, M. • Martinet, N. • Marulli, F. • Massey, R. • Maurogordato, S. • Medinaceli, E. • Mei, S. • Mellier, Y. • Meneghetti, M. • Merlin, E. • Meylan, G. • Moscardini, L. • Nakajima, R. • Neissner, C. • Niemi, S.-M. • Padilla, C. • Paltani, S. • Pasian, F. • Pedersen, K. • Percival, W. J. • Pettorino, V. • Pires, S. • Polenta, G. • Poncet, M. • Popa, L. A. • Pozzetti, L. • Raison, F. • Rebolo, R. • Renzi, A. • Rhodes, J. • Riccio, G. • Romelli, E. • Roncarelli, M. • Rosset, C. • Rottgering, H. J. A. • Saglia, R. • Sakr, Z. • Sapone, D. • Schirmer, M. • Schneider, P. • Schrabback, T. • Secroun, A. • Sefusatti, E. • Seidel, G. • Serrano, S. • Sirignano, C. • Sirri, G. • Stanco, L. • Steinwagner, J. • Tallada-Crespí, P. • Taylor, A. N. • Tereno, I. • Toft, S. • Toledo-Moreo, R. • Torradeflot, F. • Tutusaus, I. • Valenziano, L. • Valiviita, J. • Vassallo, T. • Veropalumbo, A. • Wang, Y. • Weller, J. • Zerbi, F. M. • Zucca, E. • Burigana, C. • Scottez, V. • Sereno, M. • Viel, M.

Abstract • Galaxy clusters detected through their X-ray emission or Sunyaev─Zeldovich effect (SZE), both produced by the intracluster medium (ICM), have been successfully used in cosmological and astrophysical studies. To maximise the scientific return and robustness of such studies, complementary information from other datasets is required. Systematic cluster confirmation and redshifts of ICM-selected cluster candidates are typically provided by wide-field optical and infrared imaging surveys, which are becoming increasingly challenged by ongoing ICM-selected samples. Particularly at high redshifts (z > 1) reached by future SZE-selected samples, current large surveys may not be sufficient for this task. Deep high-resolution infrared surveys, such as those conducted with Euclid, are therefore essential to confirm the majority of high-redshift clusters in these future samples. In this context, we present an analysis of the first sizeable Euclid dataset (Q1), which overlaps with several ICM-selected cluster samples. We applied an adaptation of the MCMF cluster redshift and confirmation tool to Euclid data to estimate key cluster properties, including redshift and richness, and to predict its capabilities to confirm high-redshift galaxy clusters. We find promising performance in redshift and richness estimation, particularly at high redshift. The performance in richness estimation at low redshifts (z < 0.4) is currently impacted by limitations of the Q1 dataset and are likely to improve in future data releases. By comparing MCMF measurements along random lines of sight with similar measurements from the SZE-based ACT-DR5 MCMF catalogue, we predict that the ability to confirm clusters at 1 < z < 2 using Euclid will be comparable to that of current large optical surveys at z < 0.6 and will significantly enhance the capability of cluster confirmation at high redshifts. SZE-selected cluster samples will therefore especially benefit from overlap with Euclid datasets. Through study of the five known high-z SZE-selected clusters in Q1, we identified the highest-redshift jellyfish galaxy candidate found to date in an ICM-selected cluster. This galaxy, EUCL J035330.86−504347.6, is located in the massive cluster SPT-CL J0353−5043 at z = 1.32. We also found two massive star-forming galaxies projected close to the core of ACT-CL J0350.0−4819 (z ≃ 1.46) and evidence of strong lensing features in SPT-CL J0353−5043 and SPT-CL J0421−4845. ★ This paper is published on behalf of the Euclid Consortium.

Links

• POSTSCRIPT https://www.aanda.org/10.1051/0004-6361/202556233/postscript