A1 Refereed original research article in a scientific journal
Euclid preparation: LX. The use of HST images as input for weak-lensing image simulations
Authors: Scognamiglio, D.; Schrabback, T.; Tewes, M.; Gillis, B.; Hoekstra, H.; Huff, E. M.; Marggraf, O.; Kitching, T.; Massey, R.; Tereno, I.; Carvalho, C. S.; Robertson, A.; Congedo, G.; Aghanim, N.; Altieri, B.; Amara, A.; Andreon, S.; Auricchio, N.; Baccigalupi, C.; Baldi, M.; Bardelli, S.; Battaglia, P.; Bodendorf, C.; Bonino, D.; Branchini, E.; Brescia, M.; Brinchmann, J.; Camera, S.; Capobianco, V.; Carbone, C.; Cardone, V. F.; Carretero, J.; Casas, S.; Castander, F. J.; Castellano, M.; Castignani, G.; Cavuoti, S.; Cimatti, A.; Colodro-Conde, C.; Conselice, C. J.; Conversi, L.; Copin, Y.; Courbin, F.; Courtois, H. M.; Cropper, M.; Da Silva, A.; Degaudenzi, H.; De Lucia, G.; Di Giorgio, A. M.; Dinis, J.; Dubath, F.; Duncan, C. A. J.; Dupac, X.; Dusini, S.; Farina, M.; Farrens, S.; Ferriol, S.; Fosalba, P.; Frailis, M.; Franceschi, E.; Galeotta, S.; Giocoli, C.; Gomez-Alvarez, P.; Grazian, A.; Grupp, F.; Guzzo, L.; Haugan, S. V. H.; Holmes, W.; Hormuth, F.; Hornstrup, A.; Hudelot, P.; Jahnke, K.; Joachimi, B.; Keihanen, E.; Kermiche, S.; Kiessling, A.; Kilbinger, M.; Kubik, B.; Kuemmel, M.; Kunz, M.; Kurki-Suonio, H.; Ligori, S.; Lilje, P. B.; Lindholm, V.; Lloro, I.; Mainetti, G.; Maiorano, E.; Mansutti, O.; Markovic, K.; Martinelli, M.; Martinet, N.; Marulli, F.; Medinaceli, E.; Mei, S.; Mellier, Y.; Meneghetti, M.; Meylan, G.; Moresco, M.; Moscardini, L.; Nakajima, R.; Niemi, S. -M.; Nightingale, J. W.; Padilla, C.; Paltani, S.; Pasian, F.; Pedersen, K.; 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.; Rossetti, E.; Saglia, R.; Sakr, Z.; Sanchez, A. G.; Sapone, D.; Sartoris, B.; Scaramella, R.; Schirmer, M.; Schneider, P.; Secroun, A.; Seidel, G.; Serrano, S.; Sirignano, C.; Sirri, G.; Skottfelt, J.; Stanco, L.; Starck, J. -L.; Steinwagner, J.; Tallada-Crespi, P.; Taylor, A. N.; Teplitz, H. I.; Toledo-Moreo, R.; Torradeflot, F.; Tutusaus, I.; Valenziano, L.; Vassallo, T.; Kleijn, G. Verdoes; Veropalumbo, A.; Wang, Y.; Weller, J.; Wetzstein, M.; Zamorani, G.; Zucca, E.; Biviano, A.; Bolzonella, M.; Boucaud, A.; Bozzo, E.; Burigana, C.; Calabrese, M.; Vigo, J. A. Escartin; Gracia-Carpio, J.; Mauri, N.; Pezzotta, A.; Pontinen, M.; Porciani, C.; Scottez, V.; Tenti, M.; Viel, M.; Wiesmann, M.; Akrami, Y.; Allevato, V.; Anselmi, S.; Ballardini, M.; Blot, L.; Borgani, S.; Bruton, S.; Cabanac, R.; Calabro, A.; Cappi, A.; Castro, T.; Chambers, K. C.; Contarini, S.; Cooray, A. R.; Davini, S.; De Caro, B.; Desprez, G.; Diaz-Sanchez, A.; Di Domizio, S.; Dole, H.; Escoffier, S.; Ferrari, A. G.; Ferrero, I.; Fornari, F.; Gabarra, L.; Ganga, K.; Garcia-Bellido, J.; Gaztanaga, E.; Giacomini, F.; Gianotti, F.; Gozaliasl, G.; Hall, A.; Hemmati, S.; Hildebrandt, H.; Hjorth, J.; Munoz, A. Jimenez; Kajava, J. J. E.; Kansal, V.; Karagiannis, D.; Kirkpatrick, C. C.; Le Graet, J.; Legrand, L.; Loureiro, A.; Macias-Perez, J.; Maggio, G.; Magliocchetti, M.; Mannucci, F.; Maoli, R.; Martins, C. J. A. P.; Matthew, S.; Maurin, L.; Metcalf, R. B.; Monaco, P.; Moretti, C.; Morgante, G.; Walton, N. A.; Patrizii, L.; Popa, V.; Potter, D.; Reimberg, P.; Risso, I.; Rocci, P. -F.; Rollins, R. P.; Sahlen, M.; Schneider, A.; Sereno, M.; Simon, P.; Mancini, A. Spurio; Tanidis, K.; Tao, C.; Testera, G.; Teyssier, R.; Toft, S.; Tosi, S.; Troja, A.; Tucci, M.; Valieri, C.; Valiviita, J.; Vergani, D.; Verza, G.; Euclid Collaboration
Publisher: EDP SCIENCES S A
Publishing place: LES ULIS CEDEX A
Publication year: 2025
Journal: Astronomy and Astrophysics
Journal name in source: ASTRONOMY & ASTROPHYSICS
Journal acronym: ASTRON ASTROPHYS
Article number: A262
Volume: 694
Number of pages: 22
ISSN: 0004-6361
eISSN: 1432-0746
DOI: https://doi.org/10.1051/0004-6361/202451587
Web address : https://doi.org/10.1051/0004-6361/202451587
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/492184492
Data from the Euclid space telescope will enable cosmic shear measurements to be carried out with very small statistical errors, necessitating a corresponding level of systematic error control. A common approach to correct for shear biases involves calibrating shape measurement methods using image simulations with known input shear. Given their high resolution, galaxies observed with the Hubble Space Telescope (HST) can, in principle, be utilised to emulate Euclid observations of sheared galaxy images with realistic morphologies. In this work, we employ a GalSim-based testing environment to investigate whether uncertainties in the HST point spread function (PSF) model or in data processing techniques introduce significant biases in weak-lensing (WL) shear calibration. We used single Sersic galaxy models to simulate both HST and Euclid observations. We then 'Euclidised' our HST simulations and compared the results with the directly simulated Euclid-like images. For this comparison, we utilised a moment-based shape measurement algorithm and galaxy model fits. Through the Euclidisation procedure, we effectively reduced the residual multiplicative biases in shear measurements to sub-percent levels. This achievement was made possible by employing either the native pixel scales of the instruments, utilising the Lanczos15 interpolation kernel, correcting for noise correlations, and ensuring consistent galaxy signal-to-noise ratios between simulation branches. Alternatively, a finer pixel scale can be employed alongside deeper HST data. However, the Euclidisation procedure requires further analysis on the impact of the correlated noise, to estimate calibration bias. We found that additive biases can be mitigated by applying a post-deconvolution isotropisation in the Euclidisation set-up. Additionally, we conducted an in-depth analysis of the accuracy of TinyTim HST PSF models using star fields observed in the F606W and F814W filters. We observe that F606W images exhibit a broader scatter in the recovered best-fit focus, compared to those in the F814W filter. Estimating the focus value for the F606W filter in lower stellar density regimes has allowed us to reveal significant statistical uncertainties.
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Funding information in the publication:
DS acknowledges support from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 776247. While based at the University of Bonn, DS was a member of the International Max Planck Research School (IMPRS) for Astronomy and Astrophysics at the Universities of Bonn and Cologne. In addition, part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). The Bonn group acknowledges support from the German Federal Ministry for Economic Affairs and Climate Action (BMWK) provided by DLR under projects 50QE1103, 50QE2002, and 50QE2302. TS acknowledges support provided by the Austrian Research Promotion Agency (FFG) and the Federal Ministry of the Republic of Austria for Climate Action, Environment, Energy, Mobility, Innovation and Technology (BMK) via the Austrian Space Applications Programme with grant numbers 899537, 900565, and 911971. BG thanks UK Space Agency for funding. Part of the simulations were performed on the HPC systems Raven and Cobra of the Max Planck Computing and Data Facility (MPCDF) in Garching, Germany. We also thank the anonymous referee for improving our manuscript. The Euclid Consortium acknowledges the European Space Agency and a number of agencies and institutes that have supported the development of Euclid, in particular the Agenzia Spaziale Italiana, the Austrian Forschungsförderungsgesellschaft funded through BMK, the Belgian Science Policy, the Canadian Euclid Consortium, the Deutsches Zentrum für Luft- und Raumfahrt, the DTU Space and the Niels Bohr Institute in Denmark, the French Centre National d’Etudes Spatiales, the Fundação para a Ciência e a Tecnologia, the Hungarian Academy of Sciences, the Ministerio de Ciencia, Innovación y Universidades, the National Aeronautics and Space Administration, the National Astronomical Observatory of Japan, the Netherlandse Onderzoekschool Voor Astronomie, the Norwegian Space Agency, the Research Council of Finland, the Romanian Space Agency, the State Secretariat for Education, Research, and Innovation (SERI) at the Swiss Space Office (SSO), and the United Kingdom Space Agency. A complete and detailed list is available on the Euclid web site (http://www.euclid-ec.org).
