Euclid preparation - I. The Euclid Wide Survey

R. Scaramella , J. Amiaux (1) , Y. Mellier (1, 2) , C. Burigana (3) , C. Carvalho (4) , J.-C. Cuillandre (5) , A. da Silva , A. Derosa , J. Dinis , E. Maiorano , M. Maris , I. Tereno , R. Laureijs , T. Boenke , G. Buenadicha (6) , X. Dupac (7) , L. Gaspar Venancio , P. Gómez-Álvarez , J. Hoar (6) , J. Lorenzo Alvarez , G. Racca , G. Saavedra-Criado , J. Schwartz , R. Vavrek , M. Schirmer , H. Aussel , R. Azzollini , V. Cardone , M. Cropper , A. Ealet (8) , B. Garilli , W. Gillard (9) , B. Granett , L. Guzzo , H. Hoekstra , K. Jahnke , T. Kitching , T. Maciaszek , M. Meneghetti , L. Miller , R. Nakajima , S. Niemi , F. Pasian , W. Percival , S. Pottinger , M. Sauvage , M. Scodeggio , S. Wachter , A. Zacchei , N. Aghanim , A. Amara , T. Auphan (9) , N. Auricchio , S. Awan , A. Balestra , R. Bender , C. Bodendorf , D. Bonino , E. Branchini , S. Brau-Nogue , M. Brescia , G. Candini , V. Capobianco , C. Carbone , R. Carlberg , J. Carretero , R. Casas , F. Castander , M. Castellano , S. Cavuoti , A. Cimatti , R. Cledassou (10) , G. Congedo , C. Conselice , L. Conversi , Y. Copin (8) , L. Corcione , A. Costille , F. Courbin , H. Degaudenzi , M. Douspis , F. Dubath , C. Duncan , S. Dusini , S. Farrens , S. Ferriol (8) , P. Fosalba , N. Fourmanoit (8) , M. Frailis , E. Franceschi , P. Franzetti , M. Fumana , B. Gillis , C. Giocoli , A. Grazian , F. Grupp , S. Haugan , W. Holmes , F. Hormuth , P. Hudelot , S. Kermiche (9) , A. Kiessling , M. Kilbinger , R. Kohley , B. Kubik (8) , M. Kümmel , M. Kunz , H. Kurki-Suonio , O. Lahav , S. Ligori , P. Lilje , I. Lloro , O. Mansutti , O. Marggraf , K. Markovic , F. Marulli , R. Massey , S. Maurogordato (11) , M. Melchior , E. Merlin , G. Meylan , J. Mohr , M. Moresco , B. Morin , L. Moscardini , E. Munari , R. Nichol , C. Padilla , S. Paltani , J. Peacock , K. Pedersen , V. Pettorino , S. Pires , M. Poncet , L. Popa , L. Pozzetti , F. Raison , R. Rebolo , J. Rhodes , H.-W. Rix , M. Roncarelli , E. Rossetti , R. Saglia , P. Schneider , T. Schrabback , A. Secroun (9) , G. Seidel , S. Serrano , C. Sirignano , G. Sirri , J. Skottfelt , L. Stanco , J. Starck , P. Tallada-Crespí , D. Tavagnacco , A. Taylor , H. Teplitz , R. Toledo-Moreo , F. Torradeflot , M. Trifoglio , E. Valentijn , L. Valenziano , G. Verdoes Kleijn , Y. Wang , N. Welikala , J. Weller , M. Wetzstein , G. Zamorani , J. Zoubian (9) , S. Andreon , M. Baldi , S. Bardelli , A. Boucaud (12) , S. Camera , D. Di Ferdinando , G. Fabbian , R. Farinelli , S. Galeotta , J. Graciá-Carpio , D. Maino , E. Medinaceli , S. Mei (12) , C. Neissner , G. Polenta , A. Renzi , E. Romelli , C. Rosset (12) , F. Sureau , M. Tenti , T. Vassallo , E. Zucca , C. Baccigalupi , A. Balaguera-Antolínez , P. Battaglia , A. Biviano , S. Borgani , E. Bozzo , R. Cabanac , A. Cappi , S. Casas , G. Castignani , C. Colodro-Conde , J. Coupon , H. Courtois (8) , J. Cuby , S. de la Torre , S. Desai , H. Dole , M. Fabricius , M. Farina , P. Ferreira , F. Finelli , P. Flose-Reimberg , S. Fotopoulou , K. Ganga (12) , G. Gozaliasl , I. Hook , E. Keihanen , C. Kirkpatrick , P. Liebing , V. Lindholm , G. Mainetti (13) , M. Martinelli , N. Martinet (14) , M. Maturi , H. Mccracken , R. Metcalf , G. Morgante , J. Nightingale , A. Nucita , L. Patrizii , D. Potter , G. Riccio , A. Sánchez , D. Sapone , J. Schewtschenko , M. Schultheis , V. Scottez , R. Teyssier , I. Tutusaus , J. Valiviita , M. Viel , W. Vriend , L. Whittaker

1 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
2 IAP - Institut d'Astrophysique de Paris
3 IASF-Bo - Istituto di Astrofisica Spaziale e Fisica cosmica - Bologna
4 Université de Lisbonne
5 AIM (UMR_7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
6 ESAC - European Space Astronomy Centre
7 CESR - Centre d'étude spatiale des rayonnements
8 IP2I Lyon - Institut de Physique des 2 Infinis de Lyon
9 CPPM - Centre de Physique des Particules de Marseille
10 IN2P3 - Institut National de Physique Nucléaire et de Physique des Particules du CNRS
11 LAGRANGE - Joseph Louis LAGRANGE
12 APC (UMR_7164) - AstroParticule et Cosmologie
13 CC-IN2P3 - Centre de Calcul de l'IN2P3
14 LAM - Laboratoire d'Astrophysique de Marseille

Euclid is a mission of the European Space Agency that is designed to constrain the properties of dark energy and gravity via weak gravitational lensing and galaxy clustering. It will carry out a wide area imaging and spectroscopy survey (the Euclid Wide Survey: EWS) in visible and near-infrared bands, covering approximately 15 000 deg 2 of extragalactic sky in six years. The wide-field telescope and instruments are optimised for pristine point spread function and reduced stray light, producing very crisp images. This paper presents the building of the Euclid reference survey: the sequence of pointings of EWS, deep fields, and calibration fields, as well as spacecraft movements followed by Euclid as it operates in a step-and-stare mode from its orbit around the Lagrange point L2. Each EWS pointing has four dithered frames; we simulated the dither pattern at the pixel level to analyse the effective coverage. We used up-to-date models for the sky background to define the Euclid region-of-interest (RoI). The building of the reference survey is highly constrained from calibration cadences, spacecraft constraints, and background levels; synergies with ground-based coverage were also considered. Via purposely built software, we first generated a schedule for the calibrations and deep fields observations. On a second stage, the RoI was tiled and scheduled with EWS observations, using an algorithm optimised to prioritise the best sky areas, produce a compact coverage, and ensure thermal stability. The result is the optimised reference survey RSD_2021A, which fulfils all constraints and is a good proxy for the final solution. The current EWS covers ≈14 500 deg 2 . The limiting AB magnitudes (5 σ point-like source) achieved in its footprint are estimated to be 26.2 (visible band I E ) and 24.5 (for near infrared bands Y E , J E , H E ); for spectroscopy, the H α line flux limit is 2 × 10 −16 erg −1 cm −2 s −1 at 1600 nm; and for diffuse emission, the surface brightness limits are 29.8 (visible band) and 28.4 (near infrared bands) mag arcsec −2 .

Domains: Sciences of the Universe [physics]; Physics [physics]; Astrophysics [astro-ph]; Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]; Physics [physics]; Astrophysics [astro-ph]; Instrumentation and Methods for Astrophysic [astro-ph.IM]; Sciences of the Universe [physics]; Astrophysics [astro-ph]

R. Scaramella, J. Amiaux, Y. Mellier, C. Burigana, C. Carvalho, et al.. Euclid preparation - I. The Euclid Wide Survey. Astronomy and Astrophysics - A&A, 2022, 662, pp.A112. ⟨10.1051/0004-6361/202141938⟩. ⟨hal-03866201v2⟩