Euclid VI. NISP-P optical ghosts
Instrumentation and Methods for Astrophysics
2026-03-18 v1
Abstract
The Near-Infrared Spectrometer and Photometer (NISP) onboard Euclid includes several optical elements in its path, which introduce artefacts into the data from non-nominal light paths. To ensure uncontaminated source photometry, these artefacts must be accurately accounted for. This paper focuses on two specific optical features in NISP's photometric data (NISP-P): ghosts caused by the telescope's dichroic beamsplitter, and the bandpass filters within the NISP fore-optics. Both ghost types exhibit a characteristic morphology and are offset from the originating stars. The offsets are well modelled using 2D polynomials, with only stars brighter than approximately 10 magnitudes in each filter producing significant ghost contributions. The masking radii for these ghosts depend on both the source-star brightness and the filter wavelength, ranging from 20 to 40 pixels. We present the final relations and models used in the near-infrared (NIR) data pipeline to mask these ghosts for Euclid's Quick Data Release (Q1).
Cite
@article{arxiv.2507.11072,
title = {Euclid VI. NISP-P optical ghosts},
author = {Euclid Collaboration and K. Paterson and M. Schirmer and K. Okumura and B. Venemans and K. Jahnke and N. Aghanim and B. Altieri and A. Amara and S. Andreon and C. Baccigalupi and M. Baldi and A. Balestra and S. Bardelli and P. Battaglia and A. Biviano and A. Bonchi and E. Branchini and M. Brescia and J. Brinchmann and S. Camera and G. Cañas-Herrera and V. Capobianco and J. Carretero and S. Casas and M. Castellano and G. Castignani and S. Cavuoti and K. C. Chambers and A. Cimatti and C. Colodro-Conde and G. Congedo and C. J. Conselice and L. Conversi and Y. Copin and F. Courbin and H. M. Courtois and A. Da Silva and R. da Silva and H. Degaudenzi and G. De Lucia and A. M. Di Giorgio and J. Dinis 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 S. Fotopoulou and N. Fourmanoit and M. Frailis and E. Franceschi and P. Franzetti and S. Galeotta and K. George and W. Gillard and B. Gillis and C. Giocoli and J. Gracia-Carpio and B. R. Granett and A. Grazian and F. Grupp and L. Guzzo and S. V. H. Haugan and H. Hoekstra and W. Holmes and F. Hormuth and A. Hornstrup and P. Hudelot and M. Jhabvala and E. Keihänen and S. Kermiche and A. Kiessling and R. Kohley and B. Kubik and M. Kümmel and M. Kunz and H. Kurki-Suonio and A. M. C. Le Brun and D. Le Mignant 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 K. Markovic and M. Martinelli and N. Martinet and F. Marulli and R. Massey and H. J. McCracken and E. Medinaceli and S. Mei and M. Meneghetti and E. Merlin and G. Meylan and A. Mora and M. Moresco and L. Moscardini and R. Nakajima and C. Neissner and R. C. Nichol and S. -M. Niemi and J. W. Nightingale 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 L. Pozzetti and F. Raison and R. Rebolo and A. Renzi and J. Rhodes and G. Riccio and E. Romelli and M. Roncarelli and E. Rossetti and R. Saglia and Z. Sakr and A. G. Sánchez and D. Sapone and B. Sartoris and J. A. Schewtschenko and P. Schneider and T. Schrabback and A. Secroun and E. Sefusatti and G. Seidel and M. Seiffert 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 L. Valenziano and J. Valiviita and T. Vassallo and G. Verdoes Kleijn and A. Veropalumbo and Y. Wang and J. Weller and A. Zacchei and G. Zamorani and I. A. Zinchenko and E. Zucca and V. Allevato and M. Ballardini and M. Bolzonella and E. Bozzo and C. Burigana and R. Cabanac and M. Calabrese and P. Casenove and D. Di Ferdinando and J. A. Escartin Vigo and L. Gabarra and S. Matthew and N. Mauri and R. B. Metcalf and A. A. Nucita and A. Pezzotta and M. Pöntinen and C. Porciani and V. Scottez and M. Tenti and M. Viel and M. Wiesmann and Y. Akrami and I. T. Andika and S. Anselmi and M. Archidiacono and F. Atrio-Barandela and D. Bertacca and M. Bethermin and A. Blanchard and L. Blot and S. Borgani and M. L. Brown and S. Bruton and A. Calabro and A. Cappi and F. Caro and C. S. Carvalho and T. Castro and R. Chary and F. Cogato and S. Conseil 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 P. Dimauro and A. Enia and Y. Fang and A. M. N. Ferguson and A. G. Ferrari and A. Finoguenov and A. Franco and K. Ganga and J. García-Bellido and T. Gasparetto and V. Gautard and E. Gaztanaga and F. Giacomini and F. Gianotti and G. Gozaliasl and A. Gregorio and M. Guidi and C. M. Gutierrez and A. Hall and W. G. Hartley and S. Hemmati and C. Hernández-Monteagudo and H. Hildebrandt and J. Hjorth and J. J. E. Kajava and Y. Kang and V. Kansal and D. Karagiannis and K. Kiiveri and C. C. Kirkpatrick and S. Kruk and J. Le Graet and L. Legrand and M. Lembo and F. Lepori and G. Leroy and J. Lesgourgues and L. Leuzzi and T. I. Liaudat and S. J. Liu and A. Loureiro and J. Macias-Perez and G. Maggio and M. Magliocchetti and F. Mannucci and R. Maoli and J. Martín-Fleitas and C. J. A. P. Martins and L. Maurin and M. Miluzio and P. Monaco 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 F. Passalacqua and L. Patrizii and A. Pisani and D. Potter and S. Quai and M. Radovich and P. Reimberg and I. Risso and S. Sacquegna and M. Sahlén and E. Sarpa and A. Schneider and M. Schultheis and D. Sciotti and E. Sellentin and M. Sereno and A. Shulevski and L. C. Smith and J. Stadel and K. Tanidis and C. Tao and G. Testera and R. Teyssier and S. Tosi and A. Troja and M. Tucci and C. Valieri and A. Venhola and D. Vergani and G. Verza and P. Vielzeuf and N. A. Walton},
journal= {arXiv preprint arXiv:2507.11072},
year = {2026}
}
Comments
13 pages, 10 figures, submitted