Euclid: Early Release Observations. NISP-only sources and the search for luminous z=6-8 galaxies
Authors: Weaver J.R. , Taamoli S. , McPartland C.J.R. , Zalesky L. , Allen N. , Toft S. , Sanders D.B. , Atek H. , Bowler R.A. , Stern D. , Conselice C.J. , Mobasher B. , Szapudi I. , Eisenhardt P.R.M. , Murphree G. , Valdes I. , Ito K. , Belladitta S. , Oesch P.A. , Serjeant S. , Mortlock D.J. , Hatch N.A. , Kluge M. , Milvang-Jensen B. , Rodighiero G. , Ba\ nados E. , Diego J.M. , Gavazzi R. , Congedo G. , Shuntov M. , Dole H. , Rocci P.-F. , Saifollahi T. , Miluzio M. , Ezziati M. , Hughes A.C.N. , Cuillandre J.-C. , Laureijs R. , Paltani S. , Schirmer M. , Stone C. , Aghanim N. , Altieri B. , Amara A. , Andreon S. , Auricchio N. , Baldi M. , Balestra A. , Bardelli S. , Bender R. , Bodendorf C. , Bonino D. , Branchini E. , Brescia M. , Brinchmann J. , Camera S. , Capobianco V. , Carbone C. , Cardone V.F. , Carretero J. , Casas S. , Castander F.J. , Castellano M. , Cavuoti S. , Cimatti A. , Conversi L. , Copin Y. , Corcione L. , Courbin F. , Courtois H.M. , Da Silva A. , Degaudenzi H. , Di Giorgio A.M. , Dinis J. , Douspis M. , Dubath F. , Dupac X. , Ealet A. , Farina M. , Farrens S. , Ferriol S. , Fotopoulou S. , Frailis M. , Franceschi E. , Franzetti P. , Galeotta S. , Gillard W. , Gillis B. , Giocoli C. , G'omez-Alvarez P. , Grazian A. , Grupp F. , Guzzo L. , Haugan S.V.H. , Hoar J. , Hoekstra H. , Holmes W. , Hook I. , Hormuth F. , Hornstrup A. , Hudelot P. , Jahnke K. , Jhabvala M. , Keih\"anen E. , Kermiche S. , Kiessling A. , Kitching T. , Kubik B. , K\"ummel M. , Kunz M. , Kurki-Suonio H. , Lahav O. , Le Mignant D. , Ligori S. , Lilje P.B. , Lindholm V. , Lloro I. , Maino D. , Maiorano E. , Mansutti O. , Marggraf O. , Markovic K. , Martinet N. , Marulli F. , Massey R. , Masters D.C. , Maurogordato S. , McCracken H.J. , Medinaceli E. , Mei S. , Melchior M. , Mellier Y. , Meneghetti M. , Merlin E. , Meylan G. , Mohr J. , Moresco M. , Moscardini L. , Nakajima R. , Nichol R.C. , Niemi S.-M. , Padilla C. , Pasian F. , Pedersen K. , Percival W.J. , Pettorino V. , Pires S. , Polenta G. , Poncet M. , Popa L.A. , Pozzetti L. , Raison F. , Renzi A. , Rhodes J. , Riccio G. , Romelli E. , Roncarelli M. , Rossetti E. , Saglia R. , Sapone D. , Schneider P. , Schrabback T. , Secroun A. , Seidel G. , Serrano S. , Sirignano C. , Sirri G. , Stanco L. , i  , Taylor A.N. , Teplitz H.I. , Tereno I. , Toledo-Moreo R. , Tutusaus I. , Valenziano L. , Vassallo T. , Veropalumbo A. , Wang Y. , Weller J. , Zucca E. , Burigana C. , Castignani G. , Sakr Z. , Scottez V. , Viel M. , Simon P. , Martin-Fleitas J. , Scott D. 
Published: August 2024

This paper presents a search for high redshift galaxies from the Euclid Early Release Observations program `Magnifying Lens.' The 1.5\,$ area covered by the twin Abell lensing cluster fields is comparable in size to the few other deep near-infrared surveys such as COSMOS, and so provides an opportunity to significantly increase known samples of rare UV-bright galaxies at $z UV Beyond their still uncertain role in reionisation, these UV-bright galaxies are ideal laboratories from which to study galaxy formation and constrain the bright-end of the UV luminosity function. Of the sources detected from a combined and NISP detection image, 168 do not have any appreciable VIS/ flux. These objects span a range in spectral colours, separated into two classes: 139 extremely red sources; and 29 Lyman-break galaxy candidates. Best-fit redshifts and spectral templates suggest the former is composed of both $z dusty star-forming galaxies and $z quiescent systems. The latter is composed of more homogeneous Lyman-break galaxies at $z In both cases, contamination by L- and T-type dwarfs cannot be ruled out with images alone. Additional contamination from instrumental persistence is investigated using a novel time series analysis. This work lays the foundation for future searches within the Euclid Deep Fields, where thousands more $z Lyman-break systems and extremely red sources will be identified.