Euclid. Properties and performance of the NISP signal estimator
Abstract
The Euclid spacecraft, located at the second Lagrangian point of the Sun-Earth system, hosts the Near-Infrared Spectrometer and Photometer (NISP) instrument. NISP is equipped with a mosaic of 16 HgCdTe-based detectors to acquire near-infrared photometric and spectroscopic data. To meet the spacecraft's constraints on computational resources and telemetry bandwidth, the near-infrared signal is processed onboard via a dedicated hardware-software architecture designed to fulfil the stringent Euclid's data-quality requirements. A custom application software, running on the two NISP data processing units, implements the NISP signal estimator: an ad-hoc algorithm which delivers accurate flux measurements and simultaneously estimates the quality of signal estimation through the quality factor parameter. This paper investigates the properties of the NISP signal estimator by evaluating its performance during the early flight operations of the NISP instrument. First, we revisit the assumptions on which the inference of the near-infrared signal is based and investigate the origin of the main systematics of the signal estimator through Monte Carlo simulations. Then, we test the flight performance of the NISP signal estimator. Results indicate a systematic bias lower than 0.01 e/s for 99% of the NISP pixel array, well within the noise budget of the estimated signal. We also derive an analytical expression for the variance of the NISP signal estimator, demonstrating its validity, particularly when the covariance matrix is not pre-computed. Finally, we provide a robust statistical framework to interpret the QF parameter, analyse its dependence on the signal estimator bias, and show its sensitivity to cosmic ray hits on NISP detectors. Our findings corroborate previous results on the NISP signal estimator and suggest a leading-order correction based on the agreement between flight data and simulations.
Cite
@article{arxiv.2602.03574,
title = {Euclid. Properties and performance of the NISP signal estimator},
author = {Euclid Collaboration and F. Cogato and B. Kubik and R. Barbier and S. Conseil and E. Medinaceli and Y. Copin and E. Franceschi and L. Valenziano and N. Aghanim and B. Altieri and S. Andreon and N. Auricchio and C. Baccigalupi and M. Baldi and A. Balestra and S. Bardelli and P. Battaglia and A. Biviano and E. Branchini and M. Brescia and J. Brinchmann and S. Camera and G. Cañas-Herrera and V. Capobianco and C. Carbone and J. Carretero and S. Casas and M. Castellano and G. Castignani and S. Cavuoti and A. Cimatti and C. Colodro-Conde and G. Congedo and C. J. Conselice and L. Conversi and L. Corcione and A. Costille and F. Courbin and H. M. Courtois and R. da Silva and H. Degaudenzi and G. De Lucia and H. Dole and F. Dubath and X. Dupac and S. Dusini and A. Ealet and S. Escoffier and M. Farina and R. Farinelli and F. Faustini and S. Ferriol and F. Finelli and N. Fourmanoit and M. Frailis and M. Fumana and S. Galeotta and K. George and W. Gillard and B. Gillis and C. Giocoli and J. Gracia-Carpio and A. Grazian and F. Grupp and S. V. H. Haugan and W. Holmes and F. Hormuth and A. Hornstrup and P. Hudelot and K. Jahnke and M. Jhabvala and E. Keihänen and S. Kermiche and A. Kiessling and R. Kohley and M. Kümmel and M. Kunz and H. Kurki-Suonio and A. M. C. Le Brun and S. Ligori and P. B. Lilje and V. Lindholm and I. Lloro and G. Mainetti and D. Maino and E. Maiorano and O. Mansutti and S. Marcin and O. Marggraf and M. Martinelli and N. Martinet and F. Marulli and R. J. Massey and S. Mei and Y. Mellier and M. Meneghetti and E. Merlin and G. Meylan and A. Mora and M. Moresco and L. Moscardini and C. Neissner and S. -M. Niemi and C. Padilla and S. Paltani and F. Pasian and K. Pedersen and W. J. Percival and V. Pettorino and S. Pires and G. Polenta and M. Poncet and L. A. Popa and F. Raison and A. Renzi and J. Rhodes and G. Riccio and E. Romelli and M. Roncarelli and C. Rosset and E. Rossetti and R. Saglia and Z. Sakr and A. G. Sánchez and D. Sapone and B. Sartoris and M. Schirmer and P. Schneider and M. Scodeggio and A. Secroun and G. Seidel and S. Serrano and P. Simon and C. Sirignano and G. Sirri and L. Stanco and J. Steinwagner and P. Tallada-Crespí and D. Tavagnacco and A. N. Taylor and I. Tereno and S. Toft and R. Toledo-Moreo and F. Torradeflot and I. Tutusaus and J. Valiviita and T. Vassallo and A. Veropalumbo and Y. Wang and J. Weller and A. Zacchei and F. M. Zerbi and E. Zucca and M. Ballardini and M. Bolzonella and E. Bozzo and C. Burigana and R. Cabanac and M. Calabrese and A. Cappi and T. Castro and J. A. Escartin Vigo and G. Fabbian and L. Gabarra and J. García-Bellido and V. Gautard and S. Hemmati and J. Macias-Perez and R. Maoli and J. Martín-Fleitas and N. Mauri and R. B. Metcalf and P. Monaco and A. Pezzotta and M. Pöntinen and I. Risso and V. Scottez and M. Sereno and M. Tenti and M. Tucci and M. Viel and M. Wiesmann and Y. Akrami and G. Alguero and I. T. Andika and G. Angora and S. Anselmi and M. Archidiacono and F. Atrio-Barandela and L. Bazzanini and D. Bertacca and M. Bethermin and F. Beutler and A. Blanchard and L. Blot and M. Bonici and S. Borgani and M. L. Brown and S. Bruton and A. Calabro and B. Camacho Quevedo and F. Caro and C. S. Carvalho and Y. Charles and A. R. Cooray and O. Cucciati and S. Davini and F. De Paolis and G. Desprez and A. Díaz-Sánchez and S. Di Domizio and J. M. Diego and V. Duret and M. Y. Elkhashab and A. Enia and Y. Fang and A. G. Ferrari and A. Finoguenov and A. Fontana and A. Franco and K. Ganga and T. Gasparetto and E. Gaztanaga and F. Giacomini and F. Gianotti and G. Gozaliasl and A. Gruppuso and M. Guidi and C. M. Gutierrez and A. Hall and H. Hildebrandt and J. Hjorth and J. J. E. Kajava and Y. Kang and V. Kansal and D. Karagiannis and K. Kiiveri and J. Kim and C. C. Kirkpatrick and S. Kruk and M. Lattanzi and L. Legrand and F. Lepori and G. Leroy and G. F. Lesci and J. Lesgourgues and T. I. Liaudat and M. Magliocchetti and A. Manjón-García and F. Mannucci and C. J. A. P. Martins and L. Maurin and M. Miluzio and A. Montoro and C. Moretti and G. Morgante and S. Nadathur and K. Naidoo and P. Natoli and A. Navarro-Alsina and S. Nesseris and L. Pagano and E. Palazzi and D. Paoletti and F. Passalacqua and K. Paterson and L. Patrizii and A. Pisani and D. Potter and G. W. Pratt and S. Quai and M. Radovich and W. Roster and S. Sacquegna and M. Sahlén and D. B. Sanders and E. Sarpa and A. Schneider and D. Sciotti and E. Sellentin and L. C. Smith and K. Tanidis and F. Tarsitano and G. Testera and R. Teyssier and S. Tosi and A. Troja and A. Venhola and D. Vergani and G. Verza and P. Vielzeuf and S. Vinciguerra and N. A. Walton and A. H. Wright},
journal= {arXiv preprint arXiv:2602.03574},
year = {2026}
}