A1 Refereed original research article in a scientific journal
Euclid: IV. The NISP Calibration Unit
Authors: Hormuth, F.; Jahnke, K.; Schirmer, M.; Lee C., G.-Y.; Scott, T.; Barbier, R.; Ferriol, S.; Gillard, W.; Grupp, F.; Holmes, R.; Holmes, W.; Kubik, B.; Macias-Perez, J.; Laurent, M.; Marpaud, J.; Marton, M.; Medinaceli, E.; Morgante, G.; Toledo-Moreo, R.; Trifoglio, M.; Rix, Hans-Walter; Secroun, A.; Seiffert, M.; Stassi, P.; Wachter, S.; Gutierrez C., M.; Vescovi, C.; Amara, A.; Andreon, S.; Auricchio, N.; Baccigalupi, C.; Baldi, M.; Balestra, A.; Bardelli, S.; Battaglia, P.; Bender, R.; Bodendorf, C.; Bonino, D.; Branchini, E.; Brescia, M.; Brinchmann, J.; Camera, S.; Capobianco, V.; Carbone, C.; Cardone V., F.; Carretero, J.; Casas, R.; Casas, S.; Castellano, M.; Castignani, G.; Cavuoti, S.; Cimatti, A.; Colodro-Conde, C.; Congedo, G.; Conselice C., J.; Conversi, L.; Copin, Y.; Corcione, L.; Courbin, F.; Courtois H., M.; Da Silva, A.; Degaudenzi, H.; De Lucia, G.; Dinis, J.; Douspis, M.; Dubath, F.; Ducret, F.; Dupac, X.; Dusini, S.; Fabricius, M.; Farina, M.; Farrens, S.; Faustini, F.; Fotopoulou, S.; Fourmanoit, N.; Frailis, M.; Franceschi, E.; Franzetti, P.; Fumana, M.; Galeotta, S.; Garilli, B.; George, K.; Gillis, B.; Giocoli, C.; Grazian, A.; Guzzo, L.; Haugan S. V., H.; Hoekstra, H.; Hook, I.; Hornstrup, A.; Hudelot, P.; Jhabvala, M.; Keihänen, E.; Kermiche, S.; Kiessling, A.; Kilbinger, M.; Kitching, T.; Kohley, R.; Kümmel, M.; Kunz, M.; Kurki-Suonio, H.; Le Mignant, D.; Ligori, S.; Lilje P., B.; Lindholm, V.; Lloro, I.; Mainetti, G.; Maiorano, E.; Mansutti, O.; Marcin, S.; Marggraf, O.; Markovic, K.; Martinelli, M.; Martinet, N.; Marulli, F.; Massey, R.; Maurogordato, S.; McCracken H., J.; Mei, S.; Melchior, M.; Mellier, Y.; Meneghetti, M.; Merlin, E.; Meylan, G.; Mohr J., J.; Moresco, M.; Morris P., W.; Moscardini, L.; Munari, E.; Nakajima, R.; Neissner, C.; Nichol R., C.; Niemi, S.-M.; Nightingale J., W.; Padilla, C.; Paech, K.; Paltani, S.; Pasian, F.; Pedersen, K.; Percival W., J.; Pettorino, V.; Pires, S.; Polenta, G.; Poncet, M.; Popa L., A.; Raison, F.; Rebolo, R.; Renzi, A.; Rhodes, J.; Riccio, G.; Romelli, E.; Roncarelli, M.; Rossetti, E.; Rusholme, B.; Saglia, R.; Sakr, Z.; Sánchez A., G.; Sapone, D.; Sartoris, B.; Sauvage, M.; Schewtschenko J., A.; Schneider, P.; Schrabback, T.; Sefusatti, E.; Seidel, G.; Serrano, S.; Sirignano, C.; Sirri, G.; Smadja, G.; Stanco, L.; Steinwagner, J.; Tallada-Crespí, P.; Tavagnacco, D.; Taylor A., N.; Teplitz H., I.; Tereno, I.; Torradeflot, F.; Tutusaus, I.; Valenziano, L.; Vassallo, T.; Veropalumbo, A.; Wang, Y.; Weller, J.; Zacchei, A.; Zamorani, G.; Zerbi F., M.; Zucca, E.; Biviano, A.; Bolzonella, M.; Boucaud, A.; Bozzo, E.; Burigana, C.; Calabrese, M.; Di Ferdinando, D.; Escartin Vigo J., A.; Farinelli, R.; Gracia-Carpio, J.; Kazandjian M., V.; Mauri, N.; Scottez, V.; Tenti, M.; Viel, M.; Wiesmann, M.; Akrami, Y.; Allevato, V.; Anselmi, S.; Aubourg, E.; Ballardini, M.; Bethermin, M.; Blanchard, A.; Blot, L.; Borgani, S.; Borlaff A., S.; Borsato, E.; Bruton, S.; Cabanac, R.; Calabro, A.; Canas-Herrera, G.; Cappi, A.; Carvalho C., S.; Casenove, P.; Castro, T.; Chambers K., C.; Charles, Y.; Contarini, S.; Cooray A., R.; Cucciati, O.; Davini, S.; De Caro, B.; de la Torre, S.; Desprez, G.; Díaz-Sánchez, A.; Diaz J., J.; Di Domizio, S.; Dole, H.; Escoffier, S.; Ferrari A., G.; Ferreira P., G.; Ferrero, I.; Finelli, F.; Fontana, A.; Fornari, F.; Gabarra, L.; Ganga, K.; García-Bellido, J.; Gaztanaga, E.; Giacomini, F.; Gozaliasl, G.; Hall, A.; Hartley W., G.; Hildebrandt, H.; Hjorth, J.; Huertas-Company, M.; Ilbert, O.; Jacobson, J.; Jimenez Muñoz, A.; Joudaki, S.; Kajava J. J., E.; Kansal, V.; Karagiannis, D.; Kirkpatrick C., C.; Laudisio, F.; Legrand, L.; Libet, G.; Loureiro, A.; Maggio, G.; Magliocchetti, M.; Mancini, C.; Mannucci, F.; Maoli, R.; Martins C. J. A., P.; Matthew, S.; Maurin, L.; Metcalf R., B.; Miluzio, M.; Moretti, C.; Nadathur, S.; Walton Nicholas, A.; Patrizii, L.; Pezzotta, A.; Pöntinen, M.; Popa, V.; Porciani, C.; Potter, D.; Risso, I.; Rocci, P.-F.; Rollins R., P.; Sahlén, M.; Scarlata, C.; Schneider, A.; Schultheis, M.; Sereno, M.; Shulevski, A.; Silvestri, A.; Simon, P.; Spurio Mancini, A.; Stadel, J.; Tao, C.; Testera, G.; Teyssier, R.; Toft, S.; Tosi, S.; Troja, A.; Tucci, M.; Valieri, C.; Valiviita, J.; Vergani, D.; Verza, G.; Zalesky, L.; Archidiacono, M.; Atrio-Barandela, F.; Bouvard, T.; Caro, F.; Dimauro, P.; Fang, Y.; Ferguson A. M., N.; Finoguenov, A.; Gasparetto, T.; Le Brun A. M., C.; Le Graet, J.; Liaudat T., I.; Montoro, A.; Murray, C.; Oguri, M.; Pagano, L.; Paoletti, D.; Sarpa, E.; Tanidis, K.; Vernizzi, F.; Viitanen, A.; Kovačić, I.; Lesgourgues, J.; Martín-Fleitas, J.; Mora, A.; Euclid Collaboration
Publisher: EDP Sciences
Publication year: 2025
Journal: Astronomy and Astrophysics
Journal name in source: Astronomy & Astrophysics
Article number: A4
Volume: 697
ISSN: 0004-6361
eISSN: 1432-0746
DOI: https://doi.org/10.1051/0004-6361/202450345
Web address : https://doi.org/10.1051/0004-6361/202450345
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/492323316
The near-infrared calibration unit (NI-CU) on board Euclid’s Near-Infrared Spectrometer and Photometer (NISP) is the first astronomical calibration lamp based on light-emitting diodes (LEDs) to be operated in space. Euclid is a mission in ESA’s Cosmic Vision 2015–2025 framework to explore the dark universe and provide a next-level characterisation of the nature of gravitation, dark matter, and dark energy. Calibrating photometric and spectrometric measurements of galaxies to better than 1.5% accuracy in a survey homogeneously mapping ∼14 000 deg2 of extragalactic sky requires a very detailed characterisation of near-infrared (NIR) detector properties as well as constant monitoring of them in flight. To cover two of the main contributions – relative pixel-to-pixel sensitivity and non-linearity characteristics – and to support other calibration activities, NI-CU was designed to provide spatially approximately homogeneous (<12% variations) and temporally stable illumination (0.1–0.2% over 1200 s) over the NISP detector plane with minimal power consumption and energy dissipation. NI-CU covers the spectral range ∼[900,1900] nm – at cryo-operating temperature – at five fixed independent wavelengths to capture wavelength-dependent behaviour of the detectors, with fluence over a dynamic range of ≳100 from ∼15 ph s−1 pixel−1 to >1500 ph s−1 pixel−1. For this functionality, NI-CU is based on LEDs. We describe the rationale behind the decision and design process, the challenges in sourcing the right LEDs, and the qualification process and lessons learned. We also provide a description of the completed NI-CU, its capabilities, and performance as well as its limits. NI-CU has been integrated into NISP and the Euclid satellite, and since Euclid’s launch in July 2023, it has started supporting survey operations.
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Funding information in the publication:
The authors would like to thank Coryn Bailer-Jones (on Gaia calibration), Jörg-Uwe Pott and Robert Harris (on MICADO calibration approaches), and Joshua E. Schlieder (on the Roman WFI calibration source) for interesting information and discussions. We want to further thank Thomas Blümchen for his work on an early version of NI-CU, Armin Böhm and the mechanics workshop and Ulrich Grözinger at MPIA for their support, the HIT facility at Heidelberg University Hospital and specifically Martin Härtig, the team at von Hoerner & Sulger for their work, and Frank Sackenheim, Stefan Binnewies, and Josef Pöpsel from Capella Observatory for loaning us their STX- 16803 camera. We specifically acknowledge funding of NI-CU development and MPIA’s Euclid-involvement through the Deutsches Zentrum für Luft- und Raum- fahrt (German Aerospace Center, DLR) under grants 50 QE 1202, 50 QE 2003, and 50 QE 2303. 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).
