@article{23044,
  abstract     = {We report the discovery of 31 new high-z quasars in the redshift range 6.6 < z < 7.8. These quasars were selected from approximately 3000 deg2 of sky covered during the first 1.5 years of the Euclid Wide Survey, representing the initial results of the Euclid high-z quasar search. Our candidate selection employed multiple machine-learning and probabilistic techniques applied to the EuclidIE, YE, JE, and HE images, supplemented by ancillary z-band data when available. Spectroscopic follow-up observations were carried out with Keck, Magellan, and the Large Binocular Telescope (LBT). Among the new discoveries, there are 12 quasars at z ≥ 7, more than doubling the number of previously known quasars at z ≥ 7. The newly discovered quasars exhibit 21.2 < JE < 23.2 (−25.5 < M1450 < −23.6), extending quasar studies to the faint end of the quasar luminosity function (QLF) at z ≳ 7. The quasar with the highest-z, EUCL J172902.75+641018.1 at z ≈ 7.77, sets the new redshift record for the most distant quasar ever reported. These discoveries demonstrate Euclid’s transformative role in high-z quasar discovery and set the stage for future follow-up studies of the early galaxies hosting quasars, supermassive black hole growth, and the intergalactic medium in the epoch of reionisation.},
  author       = {Yang, D. and Hennawi, J. F. and Guarneri, F. and Wolf, J. and Belladitta, S. and Schindler, J. T. and Hughes, A. C.N. and Bañados, E. and Mortlock, D. J. and Yang, J. and Wang, F. and Fan, X. and Jahnke, K. and Stern, D. and Willott, C. J. and Barth, A. J. and Rottgering, H. J.A. and Varadaraj, R. G. and Decarli, R. and Eilers, A. C. and Ezziati, M. and Fu, Y. and Huang, J. and Jin, X. and Kang, Y. and Martinez-Ramirez, L. N. and Matsuoka, Y. and Onoue, M. and Pello, R. and Remigio, R. P. and Tee, W. L. and Venemans, B. and Vietri, G. and Wang, B. and Abbo, L. J. and Atek, H. and Bisogni, S. and Bosman, S. E.I. and Bowler, R. A.A. and Conselice, C. J. and Davies, F. B. and Gutierrez, C. M. and Harikane, Y. and Rubinur, K. and Lovell, C. C. and Magliocchetti, M. and Matthee, Jorryt J and Ricci, F. and Scialpi, M. and Scott, D. and Spinoglio, L. and Tarsitano, F. and Toba, Y. and Walter, F. and Weaver, J. R. and Zamorani, G. and Altieri, B. and Amara, A. and Andreon, S. and Aussel, H. and Baccigalupi, C. and Baldi, M. and Balestra, A. and Bardelli, S. and Battaglia, P. and Biviano, A. and Branchini, E. and Brescia, M. and Camera, S. and Cañas-Herrera, G. and Capobianco, V. and Carbone, C. and Carretero, J. and Castellano, M. and Castignani, G. and Cavuoti, S. and Chambers, K. C. and Cimatti, A. and Colodro-Conde, C. and Congedo, G. and Conversi, L. and Copin, Y. and Courbin, F. and Courtois, H. M. and Cropper, M. and Cuillandre, J. C. and Degaudenzi, H. and De Lucia, G. and Dolding, C. and Dole, H. and Douspis, M. and Dubath, F. and Dupac, X. and Dusini, S. and Escoffier, S. and Farina, M. and Farinelli, R. and Ferriol, S. and Finelli, F. and Fourmanoit, N. and Frailis, M. and Franceschi, E. and Fumana, M. and Galeotta, S. and George, K. and Gillis, B. and Giocoli, C. and Gómez-Alvarez, P. and Gracia-Carpio, J. and Grazian, A. and Grupp, F. and Guzzo, L. and Gwyn, S. and Haugan, S. V.H. and Hoekstra, H. and Holmes, W. and Hook, I. M. and Hormuth, F. and Hornstrup, A. and Jhabvala, M. and Kermiche, S. and Kubik, B. and Kuijken, K. and Kümmel, M. and Kunz, M. and Kurki-Suonio, H. and Le Brun, A. M.C. and Ligori, S. and Lilje, P. B. and Lindholm, V. and Lloro, I. and Mainetti, G. and Maino, D. and Maiorano, E. and Mansutti, O. and Marggraf, O. and Martinelli, M. and Martinet, N. and Marulli, F. and Massey, R. J. and Mccracken, H. J. and Medinaceli, E. and Mei, S. and Mellier, Y. and Meneghetti, M. and Merlin, E. and Meylan, G. and Mohr, J. J. and Mora, A. and Moresco, M. and Moscardini, L. and Munari, E. and Nakajima, R. and Neissner, C. and Nichol, R. C. and Niemi, S. M. and Padilla, C. and Paltani, S. and Pasian, F. and Pedersen, K. and Percival, W. J. and Pettorino, V. and Pires, S. and Polenta, G. and Poncet, M. and Popa, L. A. and Pozzetti, L. and Racca, G. D. and Raison, F. and Rebolo, R. and Renzi, A. and Rhodes, J. and Riccio, G. and Rix, H. W. and Romelli, E. and Roncarelli, M. and Rosset, C. and Rusholme, B. and Saglia, R. and Sakr, Z. and Sapone, D. and Sauvage, M. and Schirmer, M. and Schneider, P. and Schrabback, T. and Secroun, A. and Seidel, G. and Serrano, S. and Sihvola, E. and Simon, P. and Sirignano, C. and Sirri, G. and Stanco, L. and Steinwagner, J. and Tallada-Crespí, P. and Tereno, I. and Tessore, N. and Toft, S. and Toledo-Moreo, R. and Torradeflot, F. and Tutusaus, I. and Valenziano, L. and Valiviita, J. and Vassallo, T. and Wang, Y. and Weller, J. and Zerbi, F. M. and Zucca, E. and Fabbian, G. and Huertas-Company, M. and Martín-Fleitas, J. and Monaco, P. and Scottez, V. and Viel, M.},
  issn         = {1432-0746},
  journal      = {Astronomy and Astrophysics},
  publisher    = {EDP Sciences},
  title        = {{Euclid: Discovery of 31 new quasars at 6.6 < z < 7.8}},
  doi          = {10.1051/0004-6361/202658883},
  volume       = {711},
  year         = {2026},
}