A1 Refereed original research article in a scientific journal
Euclid preparation: LIX. Angular power spectra from discrete observations
Authors: Tessore, N.; Joachimi, B.; Loureiro, A.; Hall, A.; Cañas-Herrera, G.; Tutusaus, I.; Jeffrey, N.; Naidoo, K.; McEwen, J. D.; Amara, A.; Andreon, S.; Auricchio, N.; Baccigalupi, C.; Baldi, M.; Bardelli, S.; Bernardeau, F.; Bonino, D.; Branchini, E.; Brescia, M.; Brinchmann, J.; Caillat, A.; Camera, S.; Capobianco, V.; Carbone, C.; Cardone, V. F.; Carretero, J.; Casas, S.; Castellano, M.; Castignani, G.; Cavuoti, S.; Cimatti, A.; Colodro-Conde, C.; Congedo, G.; Conselice, C. J.; Conversi, L.; Copin, Y.; Courbin, F.; Courtois, H. M.; Cropper, M.; Da Silva, A.; Degaudenzi, H.; De Lucia, G.; Dinis, J.; Dubath, F.; Duncan, C. A. J.; Dupac, X.; Dusini, S.; Farina, M.; Farrens, S.; Faustini, F.; Ferriol, S.; Frailis, M.; Franceschi, E.; Fumana, M.; Galeotta, S.; Gillard, W.; Gillis, B.; Giocoli, C.; Gómez-Alvarez, P.; Grazian, A.; Grupp, F.; Guzzo, L.; Haugan, S. V. H.; Hoekstra, H.; Holmes, W.; Hormuth, F.; Hornstrup, A.; Hudelot, P.; Jahnke, K.; Jhabvala, M.; Keihänen, E.; Kermiche, S.; Kiessling, A.; Kubik, B.; Kümmel, M.; Kunz, M.; Kurki-Suonio, H.; Ligori, S.; Lilje, P. B.; Lindholm, V.; Lloro, I.; Mainetti, G.; Maiorano, E.; Mansutti, O.; Marggraf, O.; Martinelli, M.; Martinet, N.; Marulli, F.; Massey, R.; Medinaceli, E.; Mei, S.; Melchior, M.; Mellier, Y.; Meneghetti, M.; Merlin, E.; Meylan, G.; Mohr, J. J.; Moresco, M.; Morin, B.; Moscardini, L.; Munari, E.; Nakajima, R.; 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.; Raison, F.; Renzi, A.; Rhodes, J.; Riccio, G.; Romelli, E.; Roncarelli, M.; Rossetti, E.; Saglia, R.; Sakr, Z.; Sánchez, A. G.; Sapone, D.; Sartoris, B.; Schirmer, M.; Schneider, P.; Schrabback, T.; Secroun, A.; Seidel, G.; Seiffert, M.; Serrano, S.; Sirignano, C.; Sirri, G.; Stanco, L.; Steinwagner, J.; Tallada-Crespí, P.; Taylor, A. N.; Tereno, I.; Toledo-Moreo, R.; Torradeflot, F.; Valenziano, L.; Vassallo, T.; Wang, Y.; Weller, J.; Zamorani, G.; Zucca, E.; Biviano, A.; Bolzonella, M.; Boucaud, A.; Bozzo, E.; Burigana, C.; Calabrese, M.; Di Ferdinando, D.; Escartin Vigo, J. A.; Finelli, F.; Gracia-Carpio, J.; Matthew, S.; Mauri, N.; Pezzotta, A.; Pöntinen, M.; Scottez, V.; Spurio Mancini, A.; Tenti, M.; Viel, M.; Wiesmann, M.; Akrami, Y.; Anselmi, S.; Archidiacono, M.; Atrio-Barandela, F.; Balaguera-Antolinez, A.; Ballardini, M.; Benielli, D.; Blanchard, A.; Blot, L.; Böhringer, H.; Borgani, S.; Bruton, S.; Cabanac, R.; Calabro, A.; Camacho Quevedo, B.; Cappi, A.; Caro, F.; Carvalho, C. S.; Castro, T.; Chambers, K. C.; Cooray, A. R.; de la Torre, S.; Desprez, G.; Díaz-Sánchez, A.; Di Domizio, S.; Dole, H.; Escoffier, S.; Ferrari, A. G.; Ferreira, P. G.; Ferrero, I.; Finoguenov, A.; Fontana, A.; Fornari, F.; Gabarra, L.; Ganga, K.; García-Bellido, J.; Gasparetto, T.; Gaztanaga, E.; Giacomini, F.; Gianotti, F.; Gozaliasl, G.; Gutierrez, C. M.; Hartley, W. G.; Hildebrandt, H.; Hjorth, J.; Jimenez Muñoz, A.; Joudaki, S.; Kajava, J. J. E.; Kansal, V.; Karagiannis, D.; Kirkpatrick, C. C.; Kruk, S.; Lacasa, F.; Lattanzi, M.; Le Brun, A. M. C.; Le Graet, J.; Legrand, L.; Lesgourgues, J.; Liaudat, T. I.; Macias-Perez, J.; Magliocchetti, M.; Mannucci, F.; Maoli, R.; Martín-Fleitas, J.; Martins, C. J. A. P.; Maurin, L.; Metcalf, R. B.; Miluzio, M.; Monaco, P.; Montoro, A.; Moretti, C.; Morgante, G.; Murray, C.; Nadathur, S.; Walton, N. A.; Patrizii, L.; Popa, V.; Potter, D.; Reimberg, P.; Risso, I.; Rocci, P.-F.; Rollins, R. P.; Sahlén, M.; Sarpa, E.; Schneider, A.; Sereno, M.; Simon, P.; Tanidis, K.; Tao, C.; Testera, G.; Teyssier, R.; Toft, S.; Tosi, S.; Troja, A.; Tucci, M.; Valieri, C.; Valiviita, J.; Vergani, D.; Verza, G.; Vielzeuf, P.; Brown, M. L.; Sellentin, E.; Euclid Collaboration
Publisher: EDP Sciences
Publication year: 2025
Journal: Astronomy and Astrophysics
Journal name in source: Astronomy & Astrophysics
Article number: A141
Volume: 694
ISSN: 0004-6361
eISSN: 1432-0746
DOI: https://doi.org/10.1051/0004-6361/202452018
Web address : https://doi.org/10.1051/0004-6361/202452018
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/491485603
In this paper we present the framework for measuring angular power spectra in the Euclid mission. The observables in galaxy surveys, such as galaxy clustering and cosmic shear, are not continuous fields, but discrete sets of data, obtained only at the positions of galaxies. We show how to compute the angular power spectra of such discrete data sets, without treating observations as maps of an underlying continuous field that is overlaid with a noise component. This formalism allows us to compute the exact theoretical expectations for our measured spectra, under a number of assumptions that we track explicitly. In particular, we obtain exact expressions for the additive biases ('shot noise') in angular galaxy clustering and cosmic shear. For efficient practical computations, we introduce a spin-weighted spherical convolution with a well-defined convolution theorem, which allows us to apply exact theoretical predictions to finite-resolution maps, including HEALPix. When validating our methodology, we find that our measurements are biased by less than 1% of their statistical uncertainty in simulations of Euclid's first data release.
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Funding information in the publication:
This work was supported by UK Space Agency grants ST/W002574/1 and ST/X00208X/1. AH acknowledges support through a Royal Society University Research Fellowship. GCH acknowledges support through the ESA research fellowship programme. This work has made use of CosmoHub, developed by PIC (maintained by IFAE and CIEMAT) in collaboration with ICE-CSIC. CosmoHub received funding from the Spanish government (MCIN/AEI/10.13039/501100011033), the EU NextGeneration/PRTR (PRTR-C17.I1), and the Generalitat de Catalunya. For the purpose of open access, the authors have applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising from this submission. 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 website (https://www.euclid-ec.org/).
