Euclid
Year: 2026
Type: article
Abstract: Weak lensing surveys require accurate an correction for the point spread function (PSF) when measuring galaxy shapes. For a diffraction-limited PSF, which arises in the context of space-based missions, this correction depends on each galaxy’s spectral energy distribution (SED). Therefore, sufficiently accurate knowledge of the SED is needed for every galaxy. In the Euclid mission, galaxy SED reconstruction, which is one of the tasks of the photometric-redshift processing function (PHZ PF), relies on broad- and medium-band ancillary photometry. The limited wavelength sampling of the I E passband and signal-to-noise ratio might affect the reconstruction accuracy and translate into biases in the weak lensing measurements. In this study, we present the methodology employed in the Euclid PHZ PF for reconstructing galaxy SEDs at 55 wavelengths, sampling the I E passband every 10 nm, and we assess whether it fulfils the accuracy requirements imposed on the Euclid PSF model. We employed both physics- and data-driven methods, focussing on a new approach of template-based flux correction and Gaussian processes. For validation, we introduced an SED metric whose bias translates into inaccuracies in the PSF quadrupole moments. Our findings demonstrate that Gaussian processes and template fitting meet the requirements only in specific, but complementary redshift intervals. We therefore propose a hybrid approach that leverages both methods. This solution proves effective in meeting the Euclid accuracy requirements for most of the redshift range of the survey. Finally, we investigated the impact on the SED reconstruction of a new set of 16 evenly-spaced medium-band filters for the Subaru telescope, providing quasi-spectroscopic coverage of the I E passband. This study offers promising results, ensuring accurate SED reconstruction and meeting the mission PSF requirements. This work thus provides not only the methodological foundation of galaxy SED reconstruction in the Euclid PHZ PF, but also a roadmap for future improvements using a new medium-band survey.
Source: Astronomy and Astrophysics
Authors: F. Tarsitano, C. Schreiber, H. Miyatake, A. J. Nishizawa, W. G. Hartley, L. Miller, C. Cragg, B. Csizi, H. Hildebrandt, B. Altieri, A. Amara, S. Andreon, N. Auricchio, C. Baccigalupi, M. Baldi, A. Balestra, S. Bardelli, A. Biviano, E. Branchini, M. Brescia, J. Brinchmann, S. Camera, G. Cañas-Herrera, V. Capobianco, C. Carbone, V. F. Cardone, J. Carretero, S. Casas, F. J. Castander, M. Castellano, G. Castignani, S. Cavuoti, K. C. Chambers, A. Cimatti, C. Colodro-Conde, G. Congedo, C. J. Conselice, L. Conversi, Y. Copin, F. Courbin, H. M. Courtois, M. Cropper, H. Degaudenzi, G. De Lucia, H. Dole, F. Dubath, C. A. J. Duncan, X. Dupac, S. Escoffier, M. Farina, R. Farinelli, S. Farrens, F. Faustini, S. Ferriol, F. Finelli, N. Fourmanoit, M. Frailis, E. Franceschi, M. Fumana, S. Galeotta, K. George, W. Gillard, B. Gillis, C. Giocoli, J. Gracia-Carpio, A. Grazian, F. Grupp, S. V. H. Haugan, H. Hoekstra, W. Holmes, F. Hormuth, A. Hornstrup, K. Jahnke, M. Jhabvala, B. Joachimi, E. Keihänen, S. Kermiche, A. Kiessling, B. Kubik, M. Kümmel, M. Kunz, H. Kurki-Suonio, R. Laureijs, A. M. C. Le Brun, S. Ligori, P. B. Lilje, V. Lindholm, I. Lloro, G. Mainetti, D. Maino, E. Maiorano, O. Mansutti, S. Marcin, O. Marggraf, M. Martinelli, N. Martinet, F. Marulli, R. J. Massey, E. Medinaceli, S. Mei, Y. Mellier, M. Meneghetti, E. Merlin, G. Meylan, A. Mora, M. Moresco, L. Moscardini, R. Nakajima, C. Neissner, S.-M. Niemi, C. Padilla, F. Pasian, J. A. Peacock, K. Pedersen, V. Pettorino, S. Pires, G. Polenta, M. Poncet, L. A. Popa, L. Pozzetti, F. Raison, A. Renzi, J. Rhodes, G. Riccio, E. Romelli, M. Roncarelli, C. Rosset, R. Saglia, Z. Sakr, A. G. Sánchez, D. Sapone, B. Sartoris, P. Schneider, T. Schrabback, M. Scodeggio, A. Secroun, G. Seidel, S. Serrano, P. Simon, C. Sirignano, G. Sirri, L. Stanco, J. Steinwagner, P. Tallada-Crespí, A. N. Taylor, H. I. Teplitz, I. Tereno, N. Tessore, S. Toft, R. Toledo-Moreo, F. Torradeflot, I. Tutusaus, J. Valiviita, T. Vassallo, A. Veropalumbo, Y. Wang, J. Weller, G. Zamorani, F. M. Zerbi, I. A. Zinchenko, E. Zucca, V. Allevato, M. Ballardini, M. Bolzonella, E. Bozzo, C. Burigana, R. Cabanac, A. Cappi, T. Castro, J. A. Escartin Vigo, L. Gabarra, J. García-Bellido, S. Hemmati, R. Maoli, J. Martín-Fleitas, M. Maturi, N. Mauri, R. B. Metcalf, N. Morisset, A. Pezzotta, M. Pöntinen, I. Risso, V. Scottez, M. Sereno, M. Tenti, M. Viel, M. Wiesmann, Y. Akrami, S. Alvi, I. T. Andika, G. Angora, S. Anselmi, M. Archidiacono, F. Atrio-Barandela, L. Bazzanini, D. Bertacca, M. Bethermin, A. Blanchard, L. Blot, M. Bonici, S. Borgani, M. L. Brown, S. Bruton, A. Calabro, B. Camacho Quevedo, F. Caro, C. S. Carvalho, Y. Charles, F. Cogato, S. Conseil, A. R. Cooray, O. Cucciati, S. Davini, G. Desprez, A. Díaz-Sánchez, S. Di Domizio, J. M. Diego, M. Y. Elkhashab, A. Enia, Y. Fang, A. Finoguenov, A. Franco, K. Ganga, T. Gasparetto, V. Gautard, E. Gaztanaga, F. Giacomini, F. Gianotti, G. Gozaliasl, M. Guidi, C. M. Gutierrez, A. Hall, C. Hernández-Monteagudo, J. Hjorth, J. J. E. Kajava, Y. Kang, V. Kansal, D. Karagiannis, K. Kiiveri, J. Kim, C. C. Kirkpatrick, S. Kruk, M. Lattanzi, L. Legrand, M. Lembo, F. Lepori, G. Leroy, G. F. Lesci, J. Lesgourgues, T. I. Liaudat, A. Loureiro, J. Macias-Perez, M. Magliocchetti, C. Mancini, F. Mannucci, C. J. A. P. Martins, L. Maurin, M. Miluzio, P. Monaco, A. Montoro, C. Moretti, G. Morgante, S. Nadathur, K. Naidoo, P. Natoli, A. Navarro-Alsina, S. Nesseris, M. Oguri, L. Pagano, D. Paoletti, F. Passalacqua, K. Paterson, L. Patrizii, A. Pisani, D. Potter, G. W. Pratt, S. Quai, M. Radovich, G. Rodighiero, W. Roster, S. Sacquegna, M. Sahlén, D. B. Sanders, E. Sarpa, A. Schneider, D. Sciotti, E. Sellentin, L. C. Smith, J. G. Sorce, K. Tanidis, C. Tao, G. Testera, R. Teyssier, S. Tosi, A. Troja, M. Tucci, A. Venhola, D. Vergani, G. Verza, P. Vielzeuf, S. Vinciguerra, N. A. Walton, J. R. Weaver
Institutions: University of Geneva, ETH Zurich, Institute for Particle Physics and Astrophysics, Kavli Institute for the Physics and Mathematics of the Universe, Nagoya University Institute for Advanced Research, Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, The University of Tokyo, Gifu Shotoku Gakuen University, University of Oxford, University College London, Universität Innsbruck, Ruhr University Bochum, European Space Agency, European Space Astronomy Centre, University of Surrey, Brera Astronomical Observatory, National Institute for Astrophysics, Osservatorio di Astrofisica e Scienza dello Spazio, Scuola Internazionale Superiore di Studi Avanzati, Trieste Astronomical Observatory, Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Institute for Fundamental Physics of the Universe, Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, University of Bologna, Osservatorio Astronomico di Padova, Istituto Nazionale di Fisica Nucleare, Sezione di Genova, University of Genoa, Astronomical Observatory of Capodimonte, University of Naples Federico II, European Southern Observatory, Universidade do Porto, Institute of Astrophysics and Space Sciences, Centro de Astrofísica da Universidade do Porto, European Southern Observatory, Istituto Nazionale di Fisica Nucleare, Sezione di Torino, Osservatorio Astrofisico di Torino, University of Turin, Leiden University, Leiden Observatory, European Space Research and Technology Centre, Astronomical Observatory of Rome, Istituto Nazionale di Fisica Nucleare, Sezione di Roma I, Port d'Informació Científica, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR), RWTH Aachen University, Institute of Space Sciences, Institut d'Estudis Espacials de Catalunya, Universitat Politècnica de Catalunya, Istituto Nazionale di Fisica Nucleare, Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, University of Hawaiʻi at Mānoa, University of Hawaii System, Instituto de Astrofísica de Canarias, Royal Observatory, University of Edinburgh, University of Manchester, European Space Research Institute, Lyon 1 Université, Centre National de la Recherche Scientifique, Institut National de Physique Nucléaire et de Physique des Particules, Institut de Physique des 2 Infinis de Lyon, Institució Catalana de Recerca i Estudis Avançats, Consejo Superior de Investigaciones Científicas, Institut de Ciències del Cosmos, Universitat de Barcelona, Université Paris-Saclay, Institut d'Astrophysique Spatiale, Aix-Marseille Université, Centre de physique des particules de Marseille, Institute for Space Astrophysics and Planetology, Université Paris Cité, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Astrophysique, Instrumentation et Modélisation, Agenzia Spaziale Italiana, Ludwig-Maximilians-Universität München, Max Planck Institute for Extraterrestrial Physics, University of Oslo, Jet Propulsion Laboratory, Technical University of Denmark, Max Planck Institute for Astronomy, Goddard Space Flight Center, Helsinki Institute of Physics, University of Groningen, Université Paris Sciences et Lettres, Observatoire de Paris, Sorbonne Université, Laboratoire d'Étude de l'Univers et des Phénomènes Extrêmes, SKA Observatory, Centre de Calcul de l’Institut National de Physique Nucléaire et de Physique des Particules, University of Milan, Istituto Nazionale di Fisica Nucleare, Sezione di Milano, FHNW University of Applied Sciences and Arts Northwestern Switzerland, University of Bonn, Durham University, Centre Pierre Binétruy, Institut d'Astrophysique de Paris, École Polytechnique Fédérale de Lausanne, Institute for High Energy Physics, Barcelona Institute of Science and Technology, University of Copenhagen, Centre National d'Études Spatiales, University of Padua, Istituto Nazionale di Fisica Nucleare, Sezione di Padova, Université Toulouse III - Paul Sabatier, Saint Joseph University, Heidelberg University, Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, University of Chile, California Institute of Technology, Infrared Processing and Analysis Center, University of Lisbon, Universidad Politécnica de Cartagena, University of Ferrara, Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara, Istituto di Radioastronomia di Bologna, Université Côte d'Azur, Lagrange Laboratory, Observatoire de la Côte d’Azur, Fondazione ICSC Centro Nazionale di Ricerca in High Performance Computing, Big Data e Quantum Computing, Instituto de Física Teórica, Sapienza University of Rome, Université Catholique de Lille, Case Western Reserve University, Laboratoire Univers et Théories, Universidad de Salamanca, Observatoire astronomique de Strasbourg, Université de Strasbourg, University of Waterloo, University of Trieste, University of California, Irvine, Instituto de Física de Cantabria, University of Salento, Istituto Nazionale di Fisica Nucleare, Sezione di Lecce, CEA Paris-Saclay - Etablissement de Saclay, Institut de Recherche sur les Lois Fondamentales de l'Univers, University of Portsmouth, Aalto University, Universidad de La Laguna, ARC Centre of Excellence for Dark Matter Particle Physics, Swinburne University of Technology, University of the Western Cape, University of Cambridge, University of Zurich, Stockholm University, Imperial College London, Institut polytechnique de Grenoble, Arcetri Astrophysical Observatory, Chiba University, Center for Frontier Science, Chiba University, Collurania Teramo Observatory, Uppsala University, Université de Lille, Centre de Recherche en Informatique, Signal et Automatique de Lille, Centrale Lille Institut, Princeton University, University of Oulu, The Abdus Salam International Centre for Theoretical Physics (ICTP), Flatiron Institute, Massachusetts Institute of Technology
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
OpenAlex ID: W7172006363