<i>Euclid</i>: Early Release Observations – Programme overview and pipeline for compact- and diffuse-emission photometry

The Euclid Early Release Observations (ERO) showcase Euclid ’s capabilities in advance of its main mission by targeting 17 astronomical objects, including galaxy clusters, nearby galaxies, globular clusters, and star-forming regions. A total of 24 hours of observing time was allocated in the early months of operation, and the scientific community was engaged through an early public data release. We describe the development of the ERO pipeline to create visually compelling images while simultaneously meeting the scientific demands within months of launch by leveraging a pragmatic data-driven development strategy. The pipeline’s key requirements are to preserve the image quality and to provide flux calibration and photometry for compact and extended sources. The pipeline’s five pillars are removal of instrumental signatures, astrometric calibration, photometric calibration, image stacking, and the production of science-ready catalogues for both the VIS and NISP instruments. We report a point spread function (PSF) with a full width at half maximum of 0ʺ.16 in the optical I E -band and 0ʺ.49 in the near-infrared (NIR) bands Y E , J E , and H E . Our VIS mean absolute flux calibration is accurate to about 1%, and the accuracy is 10% for NISP due to a limited calibration set; both instruments have considerable colour terms for individual sources. The median depth is 25.3 and 23.2 AB mag with a signal-to-noise ratio (S/N) of ten for galaxies, while it is 27.1 and 24.5 AB mag at an S/N of five for point sources for VIS and NISP, respectively. Euclid ’s ability to observe diffuse emission is exceptional due to its extended PSF nearly matching a pure diffraction halo, the best ever achieved by a wide-field high-resolution imaging telescope. Euclid offers unparalleled capabilities for exploring the low-surface brightness (LSB) Universe across all scales, providing high precision within a wide field of view (FoV), and opening a new observational window in the NIR. Median surface-brightness levels of 29.5 and 27.9, AB mag arcsec −2 are achieved for VIS and NISP, respectively, for detecting a 10ʺ × 10ʺ extended feature at the 1 σ level.

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Publication Details

Journal
Astronomy and Astrophysics
Published
2025-03-17
DOI
https://doi.org/10.1051/0004-6361/202450803
Citations
37
Primary Topic
Calibration and Measurement Techniques
Type
article
Field-Weighted Citation Impact
139.82
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article

Euclid: Early Release Observations – Programme overview and pipeline for compact- and diffuse-emission photometry

G. Seidel, J. Brinchmann, S. S. Larsen, M. Rejkuba et al.
37 citations
Astronomy and Astrophysics
Calibration and Measurement Techniques
139.82
article

Euclid: Early Release Observations – Programme overview and pipeline for compact- and diffuse-emission photometry

G. Seidel, J. Brinchmann, S. S. Larsen, M. Rejkuba, R. P. Saglia, P. Tallada-Crespí, S Sacquegna, O. Lahav, G. Riccio, L. Conversi, Jean‐Paul Kneib, C. Sirignano, M. Brescia, I. Hook, M. Kunz, R.A.A Bowler, C. Baccigalupi, M. Bolzonella, J. H. Knapen, M. Schirmer, F. Marulli, D. Scott, Sylvie Brau-Nogué, P. Marcos-Arenal, C. Giocoli, O. Marggraf, H. Bouy, Matteo Cantiello, N. A. Hatch, Paola Dimauro, F. Courbin, Y. Copin, F. Buitrago, A. Kiessling, Santiago Casas, A. Grazian, D. Massari, G. Sirri, S. Bardelli, Mathilde Jauzac, Sandrine Codis, E. Munari, Oliver Müller, Alberto Basset, Javier Román, V. Capobianco, L. Moscardini, Alexandre Réfrégier, S.-M Niemi, T. Schrabback, M Miluzio, S. Farrens, Stephen Gwyn, T. Saifollahi, P Gómez-Álvarez, Pierre–Alain Duc, Hans‐Walter Rix, E. Zucca, S. Andreon, S. Pires, R. Massey, T. Vassallo, R. Scaramella, S. Paltani, R. Toledo-Moreo, M. Moresco, M. Baes, J. Skottfelt, D. Sapone, S. Belladitta, Elisabeth Sola, M. Meneghetti, M. Poncet, G. Congedo, L. Valenziano, H. Dole, L.K Hunt, E. Romelli, C. Burigana, Henk Hoekstra, Sidik Isani, I. Tutusaus, H. Degaudenzi, O. Mansutti, G. Zamorani, N. Martinet, W. Gillard, F Tarsitano, John A. Peacock, K. G. Noeske, C. Padilla Aranda, E. Maiorano, Denis Erkal, A. Tsyganov, B. Gillis, Eva Schinnerer, M. Roncarelli, F. De Paolis, Conor Nally, A. Hornstrup, S. Fotopoulou, E. Medinaceli, Anna Ferré-Mateu, Maximilian Fabricius, T. Kitching, A. Lançon, A. Balestra, D. Carollo, K. Jahnkę, A. M. N. Ferguson, B. Altieri, A. Secroun, M. Farina, M Jhabvala, R. Bender, F. Pasian, A. Venhola, L. Guzzo, R. Nakajima, Stephen Serjeant, J. Weller, H. Miyatake, S. Ligori, M. Castellano, F. Grupp, S. Galeotta, Eduardo Bañados, F. Raison, E. Franceschi, W G Hartley, L Quilley, Marco Baldi, C. Bodendorf, Guillermo Buenadicha, J Martín-Fleitas, Rebecca Habas, Konrad H. Kuijken, Michelle Collins, Olivier Lai, E. Dalessandro, S. Dusini, D. Barrado, Dustin Lang, Elham Saremi, K. Markovič, Hakim Atek, B. Garilli, S. Camera, Vasily Belokurov, M. Kilbinger, R. Gavazzi, Pascal A. Oesch, J. Dinis, V. Lindholm, Petra Awad, Jason Rhodes, R. Rébolo, P.-F Rocci, Jesse B. Golden-Marx, M. Cropper, E. Keihänen, Koshy George, Raphael Zöller, S. Cavuoti, Mireia Montes, N. Auricchio, M. Frailis, Jean‐Charles Cuillandre, V Scottez, Jean-Gabriel Cuby, Karina Voggel, V. de Lapparent, Petra Schneider, P. Šimon, Masamune Oguri, C. Carbone, F. Annibali, S. Kermiche, Sune Toft, J. M. Diego, M. Žerjal, S. Serrano, G. Polenta, E. Rossetti, B. Goldman, E. L. Martı́n, P. Jablonka, E. Branchini, E. Bertin, Anthony H. Gonzalez, F. Bournaud, L. Pozzetti, Jo Bovy, R. C. Nichol, P Casenove, M. Ezziati, M Abdurro'Uf, M Mondelin, Yun Wang, A. Da Silva, L. Stančo, Xiaoyu Xu, O. Marchal, Christopher Stone, M Urbano, J. Miró Carretero, Y. Mellier, A. Cimatti, X. Dupac, I. Tereno, V. Pettorino, G. Meylan, H. Kurki‐Suonio, P. Hudelot, R. Kohley, W. A. Holmes, R. Laureijs, P. Liebing, N. Aghanim, A. Boselli, S. Maurogordato, F. Hormuth, K. Pedersen, B. Kubik, I. Lloro, Y. Ascasíbar, A Franco, M. Poulain, J. Howell, A. Mora, M Kluge, S. Ferriol, C. A. J. Duncan, M. Kümmel, A. Renzi, Y Kang
article en
37 citations

Abstract

The Euclid Early Release Observations (ERO) showcase Euclid ’s capabilities in advance of its main mission by targeting 17 astronomical objects, including galaxy clusters, nearby galaxies, globular clusters, and star-forming regions. A total of 24 hours of observing time was allocated in the early months of operation, and the scientific community was engaged through an early public data release. We describe the development of the ERO pipeline to create visually compelling images while simultaneously meeting the scientific demands within months of launch by leveraging a pragmatic data-driven development strategy. The pipeline’s key requirements are to preserve the image quality and to provide flux calibration and photometry for compact and extended sources. The pipeline’s five pillars are removal of instrumental signatures, astrometric calibration, photometric calibration, image stacking, and the production of science-ready catalogues for both the VIS and NISP instruments. We report a point spread function (PSF) with a full width at half maximum of 0ʺ.16 in the optical I E -band and 0ʺ.49 in the near-infrared (NIR) bands Y E , J E , and H E . Our VIS mean absolute flux calibration is accurate to about 1%, and the accuracy is 10% for NISP due to a limited calibration set; both instruments have considerable colour terms for individual sources. The median depth is 25.3 and 23.2 AB mag with a signal-to-noise ratio (S/N) of ten for galaxies, while it is 27.1 and 24.5 AB mag at an S/N of five for point sources for VIS and NISP, respectively. Euclid ’s ability to observe diffuse emission is exceptional due to its extended PSF nearly matching a pure diffraction halo, the best ever achieved by a wide-field high-resolution imaging telescope. Euclid offers unparalleled capabilities for exploring the low-surface brightness (LSB) Universe across all scales, providing high precision within a wide field of view (FoV), and opening a new observational window in the NIR. Median surface-brightness levels of 29.5 and 27.9, AB mag arcsec −2 are achieved for VIS and NISP, respectively, for detecting a 10ʺ × 10ʺ extended feature at the 1 σ level.

Astronomy and AstrophysicsVol. 697
Université Claude Bernard Lyon 1 (FR), International Space University (FR), Universidad de Valladolid (ES), École Normale Supérieure de Lyon (FR), University of Geneva (CH), Universidad Complutense de Madrid (ES), Leiden University (NL), California Institute of Technology (US), Herzberg Institute of Astrophysics (CA), University of Copenhagen (DK), Centre National de la Recherche Scientifique (FR), Goddard Space Flight Center (US), European Southern Observatory (DE), Institute of Space Sciences (ES), Jet Propulsion Laboratory (US), University of Helsinki (FI), Université Toulouse III - Paul Sabatier (FR), University of Bonn (DE), Scuola Internazionale Superiore di Studi Avanzati (IT), University of Padua (IT), University of Lisbon (PT), University of British Columbia (CA), University of Nottingham (GB), University of Trieste (IT), University of Salento (IT), Radboud University Nijmegen (NL), Université de Bordeaux (FR), University of Waterloo (CA), Universidad de La Laguna (ES), Chiba University (JP), Kavli Institute for the Physics and Mathematics of the Universe (JP), University of Groningen (NL), Université Fédérale de Toulouse Midi-Pyrénées (FR), Université Catholique de Lille (FR), Universidade do Porto (PT), Perimeter Institute (CA), University of Oslo (NO), University of Toronto (CA), Institut Universitaire de France (FR), Institute for High Energy Physics (ES), University of Milan (IT), Durham University (GB), Universität Innsbruck (AT), Université Côte d'Azur (FR), The Open University (GB), Aarhus University (DK), Université Paris Cité (FR), Aix-Marseille Université (FR), Université de Lille (FR), University of Cambridge (GB), University of Massachusetts Amherst (US), Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR), Université Paris-Saclay (FR), Centre National d'Études Spatiales (FR), Leibniz Institute for Astrophysics Potsdam (DE), Arcetri Astrophysical Observatory (IT), Helsinki Institute of Physics (FI), Astronomical Observatory of Rome (IT), Agenzia Spaziale Italiana (IT), Trieste Astronomical Observatory (IT), Institut d'Astrophysique de Paris (FR), Astronomical Observatory of Capodimonte (IT), European Space Agency (FR), Observatoire astronomique de Strasbourg (FR), Brera Astronomical Observatory (IT), University of Surrey (GB), University of Manchester (GB), Universidad Politécnica de Cartagena (ES), Ghent University (BE), University of Florida (US), ETH Zurich (CH), University of Bristol (GB), Sorbonne Université (FR), Técnicas Reunidas (Spain) (ES), Astrophysique, Instrumentation et Modélisation (FR), Centre de Recherche Astrophysique de Lyon (FR), Valongo Observatory (BR), Institute of Astrophysics and Space Sciences (PT), Max Planck Institute for Extraterrestrial Physics (DE), Institut d'Estudis Espacials de Catalunya (ES), European Space Astronomy Centre (ES), Centre de physique des particules de Marseille (FR), Istituto Nazionale di Fisica Nucleare, Sezione di Lecce (IT), Laboratoire d’Astrophysique de Marseille (FR), Laboratoire d'Astrophysique de Bordeaux (FR), Istituto Nazionale di Fisica Nucleare, Sezione di Torino (IT), Institute for Space Astrophysics and Planetology (IT), Institut d'Astrophysique Spatiale (FR), Istituto Nazionale di Fisica Nucleare, Sezione di Padova (IT), Osservatorio Astrofisico di Torino (IT), Royal Observatory (GB), Istituto Nazionale di Fisica Nucleare, Sezione di Napoli (IT), Max Planck Institute for Astronomy (DE), Lagrange Laboratory (FR), Centre de Recherche en Informatique (FR), Istituto di Radioastronomia di Bologna (IT), Château Gombert (FR), Cegep Edouard Montpetit (CA), Collurania Teramo Observatory (IT), Istituto Nazionale di Fisica Nucleare, Sezione di Genova (IT), Observatoire de la Côte d’Azur (FR), CEA Paris-Saclay (FR), Centro de Astrobiología (ES), Instituto de Astrofísica de Canarias (ES), Institut National de Physique Nucléaire et de Physique des Particules (FR), Istituto Nazionale di Fisica Nucleare, Sezione di Milano (IT), Institute of Space Science - INFLPR Subsidiary (RO), Istituto Nazionale di Fisica Nucleare, Sezione di Bologna (IT), Port d'Informació Científica (ES), Osservatorio Astronomico di Cagliari (IT), Istituto Nazionale di Fisica Nucleare, Sezione di Trieste (IT), Institute for Fundamental Physics of the Universe (IT), Instituto de Física de Cantabria (ES), Institute of Nuclear Physics of Lyon (FR), Osservatorio Astronomico di Padova (IT), Canada–France–Hawaii Telescope (US), National Astronomical Observatory of Japan (JP), European Space Research Institute (IT), Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (ES), Institut de Recherche en Astrophysique et Planétologie (FR), Infrared Processing and Analysis Center (US), University of Southampton (GB), Osservatorio di Astrofisica e Scienza dello Spazio, Institut de Physique des 2 Infinis de Lyon (FR), European Space Research and Technology Centre (NL), University College London (GB), École Polytechnique Fédérale de Lausanne (CH), University of Turin (IT), Nagoya University (JP), Lancaster University (GB), Université de Strasbourg (FR), University of Chile (CL), École Centrale de Lille (FR), The University of Tokyo (JP), Ludwig-Maximilians-Universität München (DE), University of Genoa (IT), National Institute for Astrophysics (IT), RWTH Aachen University (DE), Netherlands Institute for Radio Astronomy (NL), University of Bologna (IT), University of KwaZulu-Natal (ZA), Universitat Politècnica de Catalunya (ES), Technical University of Denmark (DK), University of Oulu (FI), University of Edinburgh (GB)
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