@techreport{e7451eed2cef4b868ac2c3ca67ffa184,

title = "Euclid preparation: I. The Euclid Wide Survey",

abstract = " Euclid is an ESA mission 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 (EWS) in visible and near-infrared, covering roughly 15,000 square degrees of extragalactic sky on six years. The wide-field telescope and instruments are optimized for pristine PSF and reduced straylight, producing very crisp images. This paper presents the building of the Euclid reference survey: the sequence of pointings of EWS, Deep fields, Auxiliary fields for calibrations, and 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 simulate the dither pattern at pixel level to analyse the effective coverage. We use 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 are also considered. Via purposely-built software optimized to prioritize best sky areas, produce a compact coverage, and ensure thermal stability, we generate a schedule for the Auxiliary and Deep fields observations and schedule the RoI with EWS transit observations. The resulting reference survey RSD_2021A fulfills all constraints and is a good proxy for the final solution. Its wide survey covers 14,500 square degrees. The limiting AB magnitudes ($5\sigma$ point-like source) achieved in its footprint are estimated to be 26.2 (visible) and 24.5 (near-infrared); for spectroscopy, the H$_\alpha$ line flux limit is $2\times 10^{-16}$ erg cm$^{-2}$ s$^{-1}$ at 1600 nm; and for diffuse emission the surface brightness limits are 29.8 (visible) and 28.4 (near-infrared) mag arcsec$^{-2}$. ",

keywords = "astro-ph.CO, astro-ph.IM",

author = "{Euclid Collaboration} and R. Scaramella and J. Amiaux and Y. Mellier and C. Burigana and Carvalho, {C. S.} and Cuillandre, {J. -C.} and Silva, {A. Da} and A. Derosa and J. Dinis and E. Maiorano and M. Maris and I. Tereno and R. Laureijs and T. Boenke and G. Buenadicha and X. Dupac and Venancio, {L. M. Gaspar} and P. G{\'o}mez-{\'A}lvarez and J. Hoar and Alvarez, {J. Lorenzo} and Racca, {G. D.} and G. Saavedra-Criado and J. Schwartz and R. Vavrek and M. Schirmer and H. Aussel and R. Azzollini and Cardone, {V. F.} and M. Cropper and A. Ealet and B. Garilli and W. Gillard and Granett, {B. R.} and L. Guzzo and H. Hoekstra and K. Jahnke and T. Kitching and M. Meneghetti and E. Branchini and M. Kunz and P. Schneider and C. Sirignano and Taylor, {A. N.} and Valentijn, {E. A.} and Kleijn, {G. A. Verdoes} and Y. Wang and J. Weller and S. Mei and M. Viel and W. Vriend",

note = "43 pages, 51 figures, submitted to A&A",

year = "2021",

month = aug,

day = "2",

language = "English",

series = "ArXiv",

publisher = "arXiv",

type = "WorkingPaper",

institution = "arXiv",

}