Euclid: Quick Data Release (Q1) -- LensMC shear measurement catalogue for cluster lensing science
This paper presents the first LensMC shear measurement catalogue from Euclid's Quick Release 1, validating its quality through statistical analysis and cross-checks to demonstrate the ability to constrain the lensing profiles of massive clusters out to redshift z≈2 with controlled systematic errors.
Original authors: G. Congedo (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), M. Sereno (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), H. Miyatake (Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan, Institute for Advanced Research, Nagoya University, Chikusa-ku, Nagoya, 464-8601, Japan, Kavli Institute for the Physics and Mathematics of the Universe), S. Guerrini (Université Paris Cité, Université Paris-Saclay, CEA, CNRS, AIM, F-91191, Gif-sur-Yvette, France), M. Kilbinger (Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, 91191, Gif-sur-Yvette, France), M. Radovich (INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy), H. Jansen (Universität Innsbruck, Institut für Astro- und Teilchenphysik, Technikerstr. 25/8, 6020 Innsbruck, Austria), F. Kleinebreil (Universität Innsbruck, Institut für Astro- und Teilchenphysik, Technikerstr. 25/8, 6020 Innsbruck, Austria), T. Schrabback (Universität Innsbruck, Institut für Astro- und Teilchenphysik, Technikerstr. 25/8, 6020 Innsbruck, Austria), A. N. Taylor (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), B. Altieri (ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Cañada, Madrid, Spain), L. Amendola (Institut für Theoretische Physik, University of Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany, New York University Abu Dhabi, PO Box 129188, Abu Dhabi, UAE, and Center for Astrophysics and Space Science), S. Andreon (INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy), N. Auricchio (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), C. Baccigalupi (IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy, INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy, SISSA, International School for Advanced Studies, Via Bonomea 265, 34136 Trieste TS, Italy), M. Baldi (Dipartimento di Fisica e Astronomia, Università di Bologna, Via Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), S. Bardelli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), P. Battaglia (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), A. Biviano (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy), R. P. Blake (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), E. Branchini (Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146, Genova, Italy, INFN-Sezione di Genova, Via Dodecaneso 33, 16146, Genova, Italy, INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy), M. Brescia (Department of Physics "E. Pancini", University Federico II, Via Cinthia 6, 80126, Napoli, Italy, INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy), S. Camera (Dipartimento di Fisica, Università degli Studi di Torino, Via P. Giuria 1, 10125 Torino, Italy, INFN-Sezione di Torino, Via P. Giuria 1, 10125 Torino, Italy, INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese), V. Capobianco (INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese), C. Carbone (INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy), V. F. Cardone (INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy, INFN-Sezione di Roma, Piazzale Aldo Moro, 2 - c/o Dipartimento di Fisica, Edificio G. Marconi, 00185 Roma, Italy), J. Carretero (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Port d'Informació Científica, Campus UAB, C. Albareda s/n, 08193 Bellaterra), M. Castellano (INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy), G. Castignani (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), S. Cavuoti (INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy, INFN section of Naples, Via Cinthia 6, 80126, Napoli, Italy), A. Cimatti (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Università di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), C. Colodro-Conde (Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife, Spain), L. Conversi (European Space Agency/ESRIN, Largo Galileo Galilei 1, 00044 Frascati, Roma, Italy, ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Cañada, Madrid, Spain), Y. Copin (Université Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne, F-69100, France), F. Courbin (Institut de Ciències del Cosmos, Institució Catalana de Recerca i Estudis Avançats, Institut de Ciencies de l'Espai), H. M. Courtois (UCB Lyon 1, CNRS/IN2P3, IUF, IP2I Lyon, 4 rue Enrico Fermi, 69622 Villeurbanne, France), M. Cropper (Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK), H. Degaudenzi (Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland), G. De Lucia (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), C. Dolding (Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT, UK), H. Dole (Université Paris-Saclay, CNRS, Institut d'astrophysique spatiale, 91405, Orsay, France), F. Dubath (Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland), X. Dupac (ESAC/ESA, Camino Bajo del Castillo, s/n., Urb. Villafranca del Castillo, 28692 Villanueva de la Cañada, Madrid, Spain), M. Farina (INAF-Istituto di Astrofisica e Planetologia Spaziali, via del Fosso del Cavaliere, 100, 00100 Roma, Italy), R. Farinelli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), S. Ferriol (Université Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne, F-69100, France), F. Finelli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Bologna, Via Irnerio 46, 40126 Bologna, Italy), P. Fosalba (Institut d'Estudis Espacials de Catalunya, Institute of Space Sciences), S. Fotopoulou (School of Physics, HH Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK), M. Frailis (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), M. Fumana (INAF-IASF Milano, Via Alfonso Corti 12, 20133 Milano, Italy), L. Gabarra (Department of Physics, Oxford University, Keble Road, Oxford OX1 3RH, UK), S. Galeotta (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), K. George (University Observatory, LMU Faculty of Physics, Scheinerstr.~1, 81679 Munich, Germany), B. Gillis (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), C. Giocoli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), J. Gracia-Carpio (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), A. Grazian (INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy), F. Grupp (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany, Universitäts-Sternwarte München, Fakultät für Physik, Ludwig-Maximilians-Universität München, Scheinerstr.~1, 81679 München, Germany), S. Hemmati (Caltech/IPAC, 1200 E. California Blvd., Pasadena, CA 91125, USA), M. S. Holliman (Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK), W. Holmes (Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA), I. M. Hook (Department of Physics, Lancaster University, Lancaster, LA1 4YB, UK), F. Hormuth (Felix Hormuth Engineering, Goethestr. 17, 69181 Leimen, Germany), A. Hornstrup (Technical University of Denmark, Elektrovej 327, 2800 Kgs. Lyngby, Denmark, Cosmic Dawn Center), K. Jahnke (Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany), M. Jhabvala (NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA), S. Kermiche (Aix-Marseille Université, CNRS/IN2P3, CPPM, Marseille, France), B. Kubik (Université Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, Villeurbanne, F-69100, France), M. Kümmel (Universitäts-Sternwarte München, Fakultät für Physik, Ludwig-Maximilians-Universität München, Scheinerstr.~1, 81679 München, Germany), M. Kunz (Université de Genève, Département de Physique Théorique and Centre for Astroparticle Physics, 24 quai Ernest-Ansermet, CH-1211 Genève 4, Switzerland), H. Kurki-Suonio (Department of Physics, P.O. Box 64, University of Helsinki, 00014 Helsinki, Finland, Helsinki Institute of Physics, Gustaf Hällströmin katu 2, University of Helsinki, 00014 Helsinki, Finland), A. M. C. Le Brun (Laboratoire d'etude de l'Univers et des phenomenes eXtremes, Observatoire de Paris, Université PSL, Sorbonne Université, CNRS, 92190 Meudon, France), S. Ligori (INAF-Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025 Pino Torinese), P. B. Lilje (Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, 0315 Oslo, Norway), V. Lindholm (Department of Physics, P.O. Box 64, University of Helsinki, 00014 Helsinki, Finland, Helsinki Institute of Physics, Gustaf Hällströmin katu 2, University of Helsinki, 00014 Helsinki, Finland), I. Lloro (SKAO, Jodrell Bank, Lower Withington, Macclesfield SK11 9FT, UK), M. Magliocchetti (INAF-Istituto di Astrofisica e Planetologia Spaziali, via del Fosso del Cavaliere, 100, 00100 Roma, Italy), G. Mainetti (Centre de Calcul de l'IN2P3/CNRS, 21 avenue Pierre de Coubertin 69627 Villeurbanne Cedex, France), O. Mansutti (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), O. Marggraf (Universität Bonn, Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany), M. Martinelli (INAF-Osservatorio Astronomico di Roma, Via Frascati 33, 00078 Monteporzio Catone, Italy, INFN-Sezione di Roma, Piazzale Aldo Moro, 2 - c/o Dipartimento di Fisica, Edificio G. Marconi, 00185 Roma, Italy), N. Martinet (Aix-Marseille Université, CNRS, CNES, LAM, Marseille, France), F. Marulli (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Università di Bologna, via Piero Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), R. J. Massey (Department of Physics, Institute for Computational Cosmology, Durham University, South Road, Durham, DH1 3LE, UK), E. Medinaceli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), M. Meneghetti (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), E. Merlin (INAF-Osservatorio Astronomico di Padova, Via dell'Osservatorio 5, 35122 Padova, Italy), G. Meylan (Institute of Physics, Laboratory of Astrophysics, Ecole Polytechnique Fédérale de Lausanne), A. Mora (Telespazio UK S.L. for European Space Agency), M. Moresco (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Università di Bologna, via Piero Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), C. Moretti (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy, INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy), L. Moscardini (Dipartimento di Fisica e Astronomia "Augusto Righi" - Alma Mater Studiorum Università di Bologna, via Piero Gobetti 93/2, 40129 Bologna, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy, INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), E. Munari (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy), R. Nakajima (Universität Bonn, Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany), C. Neissner (Institut de Física d'Altes Energies, Port d'Informació Científica, Campus UAB, C. Albareda s/n, 08193 Bellaterra), R. C. Nichol (School of Mathematics and Physics, University of Surrey, Guildford, Surrey, GU2 7XH, UK), S. -M. Niemi (European Space Agency/ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands), C. Padilla (Institut de Física d'Altes Energies), S. Paltani (Department of Astronomy, University of Geneva, ch. d'Ecogia 16, 1290 Versoix, Switzerland), F. Pasian (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), W. J. Percival (Waterloo Centre for Astrophysics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada, Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada, Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5, Canada), V. Pettorino (European Space Agency/ESTEC, Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands), A. Pezzotta (INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy), S. Pires (Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, 91191, Gif-sur-Yvette, France), G. Polenta (Space Science Data Center, Italian Space Agency, via del Politecnico snc, 00133 Roma, Italy), M. Poncet (Centre National d'Etudes Spatiales -- Centre spatial de Toulouse, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France), L. A. Popa (Institute of Space Science, Str. Atomistilor, nr. 409 Măgurele, Ilfov, 077125, Romania), F. Raison (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), A. Renzi (Dipartimento di Fisica e Astronomia "G. Galilei", Università di Padova, Via Marzolo 8, 35131 Padova, Italy, INFN-Padova, Via Marzolo 8, 35131 Padova, Italy, INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), J. Rhodes (Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA), G. Riccio (INAF-Osservatorio Astronomico di Capodimonte, Via Moiariello 16, 80131 Napoli, Italy), E. Romelli (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy), M. Roncarelli (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), C. Rosset (Université Paris Cité, CNRS, Astroparticule et Cosmologie, 75013 Paris, France), B. Rusholme (Caltech/IPAC, 1200 E. California Blvd., Pasadena, CA 91125, USA), R. Saglia (Universitäts-Sternwarte München, Fakultät für Physik, Ludwig-Maximilians-Universität München, Scheinerstr.~1, 81679 München, Germany, Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), Z. Sakr (Instituto de Física Teórica UAM-CSIC, Campus de Cantoblanco, 28049 Madrid, Spain, Institut de Recherche en Astrophysique et Planétologie, Université St Joseph, Faculty of Sciences, Beirut, Lebanon), A. G. Sánchez (Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), D. Sapone (Departamento de Física, FCFM, Universidad de Chile, Blanco Encalada 2008, Santiago, Chile), M. Schirmer (Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany), P. Schneider (Universität Bonn, Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany), A. Secroun (Aix-Marseille Université, CNRS/IN2P3, CPPM, Marseille, France), E. Sihvola (Department of Physics and Helsinki Institute of Physics, Gustaf Hällströmin katu 2, University of Helsinki, 00014 Helsinki, Finland), C. Sirignano (Dipartimento di Fisica e Astronomia "G. Galilei", Università di Padova, Via Marzolo 8, 35131 Padova, Italy, INFN-Padova, Via Marzolo 8, 35131 Padova, Italy), G. Sirri (INFN-Sezione di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy), L. Stanco (INFN-Padova, Via Marzolo 8, 35131 Padova, Italy), P. Tallada-Crespí (Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Port d'Informació Científica, Campus UAB, C. Albareda s/n, 08193 Bellaterra), I. Tereno (Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, Edifício C8, Campo Grande, PT1749-016 Lisboa, Portugal, Instituto de Astrofísica e Ciências do Espaço, Faculdade de Ciências, Universidade de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal), S. Toft (Cosmic Dawn Center, Niels Bohr Institute, University of Copenhagen, Jagtvej 128, 2200 Copenhagen, Denmark), R. Toledo-Moreo (Universidad Politécnica de Cartagena, Departamento de Electrónica y Tecnología de Computadoras, Plaza del Hospital 1, 30202 Cartagena, Spain, European University of Technology EUt+, European Union), F. Torradeflot (Port d'Informació Científica, Campus UAB, C. Albareda s/n, 08193 Bellaterra, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas), I. Tutusaus (Institute of Space Sciences, Institut d'Estudis Espacials de Catalunya, Institut de Recherche en Astrophysique et Planétologie), E. A. Valentijn (Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands), J. Valiviita (Department of Physics, P.O. Box 64, University of Helsinki, 00014 Helsinki, Finland, Helsinki Institute of Physics, Gustaf Hällströmin katu 2, University of Helsinki, 00014 Helsinki, Finland), T. Vassallo (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, University Observatory, LMU Faculty of Physics, Scheinerstr.~1, 81679 Munich, Germany), Y. Wang (Caltech/IPAC, 1200 E. California Blvd., Pasadena, CA 91125, USA), J. Weller (Universitäts-Sternwarte München, Fakultät für Physik, Ludwig-Maximilians-Universität München, Scheinerstr.~1, 81679 München, Germany, Max Planck Institute for Extraterrestrial Physics, Giessenbachstr. 1, 85748 Garching, Germany), A. Zacchei (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy), G. Zamorani (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), F. M. Zerbi (INAF-Osservatorio Astronomico di Brera, Via Brera 28, 20122 Milano, Italy), E. Zucca (INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy), T. Castro (INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34143 Trieste, Italy, INFN, Sezione di Trieste, Via Valerio 2, 34127 Trieste TS, Italy, IFPU, Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy, ICSC - Centro Nazionale di Ricerca in High Performance Computing, Big Data e Quantum Computing, Via Magnanelli 2, Bologna, Italy)
Original paper licensed under CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
The Big Picture: A "Test Drive" for a Giant Space Camera
Imagine the European Space Agency's Euclid telescope as a brand-new, ultra-high-definition camera launched into space. Its main job is to take a massive panoramic photo of the universe to understand how it's expanding and what it's made of. Before the camera takes its final, massive "family photo" (called Data Release 1) later this year, the team needed to take a few "test shots" to make sure the camera and the software processing the images work correctly.
This paper is the report card for those test shots. Specifically, the team looked at a small patch of sky (about 63 square degrees, which is roughly the size of 300 full moons) to see if they could accurately measure gravitational lensing.
What is Gravitational Lensing?
Think of a galaxy cluster (a huge group of galaxies) as a giant, invisible magnifying glass sitting in space. Because it has so much mass, it bends the light coming from galaxies behind it. This makes the background galaxies look slightly stretched or distorted, like looking at a fish through a curved glass bowl. By measuring exactly how stretched those background galaxies are, scientists can weigh the invisible cluster.
The Challenge: Measuring a Tiny Stretch
The problem is that the stretching is incredibly tiny. It's like trying to measure if a rubber band has been stretched by the width of a single human hair, while the rubber band is also being shaken by the wind.
To do this, the team used a new software tool called LensMC. Think of LensMC as a super-smart image editor that knows exactly how the camera lens distorts images (called the "Point Spread Function" or PSF). The software has to separate the distortion caused by the camera itself from the distortion caused by the galaxy clusters.
What They Did: The "Test Drive"
- The Data: They took the "Quick Release 1" (Q1) images from March 2025. These are real images from the Euclid telescope, not simulations.
- The Count: They processed millions of galaxies. They found about 26 galaxies per square minute of sky for bright objects, and up to 75 per square minute for very faint ones. That's like finding 75 tiny grains of sand in a single square inch of a beach.
- The Cleaning: Just like cleaning a photo before editing it, they had to remove "bad pixels" (dust on the sensor), stars (which don't stretch), and blurry blobs. They ended up with a very clean list of 84% of the original objects.
The Hiccups: Finding the "Glitches"
Even with a perfect camera, things can go wrong. The team found two main types of errors:
- Additive Bias (The "Offset"): Imagine your ruler is slightly shifted to the left. Every measurement you take is off by the same amount. The team found that their measurements were slightly shifted in a specific direction.
- Multiplicative Bias (The "Scale"): Imagine your ruler is stretched out, so every inch is actually 1.1 inches.
The Fix:
The team realized that the "glitch" (the additive bias) wasn't random; it depended on how bright the galaxy was and how big it looked. It was like realizing the ruler only gets shifted when you measure red objects, but not blue ones.
- They created a correction map. If a galaxy was bright and small, they applied one fix. If it was faint and large, they applied another.
- After applying this fix, the "glitch" disappeared, and the measurements lined up much better with what physics predicts.
The Proof: Did It Work?
To prove their new method worked, they did three "stress tests":
- The "Empty Space" Test: They looked at random spots in the sky where there are no galaxy clusters. If their software was broken, it would see fake stretching there. It didn't. The stretching was zero, as expected.
- The "Cross-Check" Test: They compared their results with data from the Dark Energy Survey (DES), a different telescope on the ground. Even though the ground telescope has a blurrier view (like looking through a foggy window) compared to Euclid's crystal-clear view, the results matched up almost perfectly. This proved their software wasn't inventing fake data.
- The "Cluster" Test: They looked at real galaxy clusters (specifically the MaDCoWS2 candidates). They measured the stretching around these clusters and found a clear signal.
- The Result: They could successfully weigh clusters as far away as 2 billion light-years (redshift z≈2) and as far out as 20 million light-years from the center of the cluster.
- The Catch: At the very edges of the map (large distances from the cluster center), especially for nearby clusters, they saw a tiny bit of "noise" or leftover error. This is likely because the clusters are so big that they hit the edge of the photo, or because the "fog" (PSF) wasn't perfectly removed at the very edges.
The Bottom Line
This paper is a "proof of concept." It says:
"We took the new Euclid camera, used our new LensMC software, and successfully measured the shape of millions of galaxies. We found a few small errors, fixed them based on the size and brightness of the galaxies, and proved that we can now weigh galaxy clusters with high precision, even for very distant ones."
Why does this matter?
It's the first time this specific software (LensMC) has been used on such a large area of real Euclid data. It confirms that when the full "family photo" (Data Release 1) arrives in 2026, the team will be ready to map the universe's structure with incredible accuracy, helping us understand the invisible forces (Dark Matter and Dark Energy) that hold the cosmos together.
In short: They built a new ruler, tested it on a small patch of the universe, found a few kinks, fixed them, and confirmed the ruler is ready for the big job ahead.
Technical Summary: Euclid Q1 LensMC Shear Measurement Catalogue for Cluster Lensing Science
Problem and Context
The Euclid mission is preparing for its Data Release 1 (DR1), which will provide extensive weak lensing data to constrain cosmological models. Prior to this full release, the Euclid Quick Release 1 (Q1) dataset, comprising 63 deg² of VIS images across three Euclid Deep Fields (EDF-North, EDF-South, and EDF-Fornax), became available in March 2025. While the primary cosmic shear requirements for Euclid are stringent (requiring multiplicative bias uncertainty σm≈2×10−3 for the full survey), cluster lensing science can tolerate slightly larger systematic errors (on the order of 1%). The challenge addressed in this paper is to produce and validate a shear measurement catalogue using the official LensMC method on this Q1 dataset. The goal is to demonstrate the capability to measure galaxy shapes and cluster lensing profiles with sufficient control of systematic errors to study galaxy clusters, including those with masses as low as 1014M⊙, out to redshifts z≈2.
Methodology
The authors applied the LensMC algorithm, the official cosmic shear method for Euclid DR1, to the Q1 mosaic stacked images. The processing pipeline involved:
- Data Input: Utilizing official EUC_MER mosaic images, PSF grids, pixel flag maps, detection catalogues, and photometric redshifts.
- PSF Modeling: Generating oversampled PSF images at arbitrary positions via spline interpolation of grid-based PSF stamps, avoiding undersampling biases.
- Object Selection: Measuring all detected objects and applying quality cuts to remove saturated sources, edge effects, bright star masks, and spurious detections. A specific cut on the flux-averaged half-light radius (rhl>0.07′′) was applied to separate stars from galaxies, effectively removing the stellar population.
- Bias Characterization and Correction:
- Additive Bias (c): A map of additive biases was generated in Field-of-View (FoV) coordinates. While no significant spatial variability was found (likely due to small data volume and stacking), a global offset was detected (c1≈−2.35×10−3, c2≈1.79×10−3). An empirical correction was developed based on galaxy magnitude (IE) and half-light radius (rhl).
- Multiplicative Bias (m): Raw multiplicative biases were estimated to be ≤1%, well within the conservative requirements for cluster lensing.
- Validation: The catalogue quality was assessed using:
- Two-point correlation functions (ξ+ and ξ−).
- Stacked lensing profiles of 495 MaDCoWS2 cluster candidates (covering z≈0.2 to $2$).
- Cross-validation with the Dark Energy Survey (DES) Year-3 catalogue using the redMaPPer cluster finder.
- Null tests using simulated random cluster positions.
Key Results
- Catalogue Depth and Density: The final catalogue achieves a surface number density of 26 arcmin⁻² for IE<24.5 and 75 arcmin⁻² for IE<27 across the 63 deg² area.
- Bias Correction: The empirical correction based on magnitude and size successfully suppressed lensing power at scales greater than 10 arcminutes, bringing the two-point correlation functions into broad agreement with a nominal ΛCDM model. However, excess power in ξ− persisted, attributed to uncalibrated redshift distributions and theoretical assumptions rather than measurement failure.
- Cluster Profiles:
- Stacked tangential shear profiles of MaDCoWS2 candidates showed consistency between raw and corrected catalogues up to a comoving radius of 20 Mpc. Beyond this scale, deviations of nearly 5σ appeared, likely due to residual systematic effects at low redshifts and large radii.
- Cross-shear profiles remained consistent with zero, indicating no strong coherent systematic errors.
- A cut on large objects (rhl<2′′) reduced the shear profile by approximately 0.5 standard deviations, suggesting a minor positive multiplicative bias from spurious large sources.
- Cross-Validation with DES: Comparisons between LensMC and DES shear measurements for matched redMaPPer clusters showed excellent agreement. The differential multiplicative bias was measured as δm=(−5±8)×10−2 and additive bias δc=(2±1)×10−4, consistent with zero bias.
- Systematic Limits: Null tests on random pointings revealed that measurements are consistent with zero signal except for low-redshift lenses at large comoving radii (>10 Mpc). This suggests residual systematics, potentially due to border effects, incomplete azimuthal coverage, or PSF residuals, which are more pronounced for the larger angular extent of low-redshift clusters.
Significance and Claims
The paper claims to present the first shear measurement catalogue produced with LensMC in anticipation of Euclid DR1. Its primary significance lies in demonstrating that, despite the modest survey volume of Q1, the combination of Euclid's image resolution and depth with the LensMC methodology allows for the successful measurement of cluster lensing profiles.
Specifically, the authors assert they can constrain the lensing profiles of clusters with masses of 1014M⊙ out to z≈2, covering nearly 10 Gyr of evolution history. They highlight that this analysis validates the ability to measure these profiles out to comoving radii of 20 Mpc with good control of systematic errors. While the authors note that the bias correction may not yet meet the strict requirements for the full Euclid Wide Survey cosmic shear analysis, it is deemed sufficient for cluster lensing science. The work serves as a critical proof-of-concept for the upcoming DR1, confirming that the methodology can handle the complexities of real data and provide robust constraints on cluster mass distributions and their evolution.
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