Bibcode
Yang, D.; Hennawi, J. F.; Guarneri, F.; Wolf, J.; Belladitta, S.; Schindler, J.-T.; Hughes, A. C. N.; Bañados, E.; Mortlock, D. J.; Yang, J.; Wang, F.; Fan, X.; Jahnke, K.; Stern, D.; Willott, C. J.; Barth, A. J.; Rottgering, H. J. A.; Varadaraj, R. G.; Decarli, R.; Eilers, A.-C.; Ezziati, M.; Fu, Y.; Huang, J.; Jin, X.; Kang, Y.; Martinez-Ramirez, L. N.; Matsuoka, Y.; Onoue, M.; Pello, R.; Remigio, R. P.; Tee, W. L.; Venemans, B.; Vietri, G.; Wang, B.; Abbo, L. J.; Atek, H.; Bisogni, S.; Bosman, S. E. I.; Bowler, R. A. A.; Conselice, C. J.; Davies, F. B.; Gutierrez, C. M.; Harikane, Y.; Rubinur, K.; Lovell, C. C.; Magliocchetti, M.; Matthee, J.; Ricci, F.; Scialpi, M.; Scott, D.; Spinoglio, L.; Tarsitano, F.; Toba, Y.; Walter, F.; Weaver, J. R.; Zamorani, G.; Altieri, B.; Amara, A.; Andreon, S.; Aussel, H.; Baccigalupi, C.; Baldi, M.; Balestra, A.; Bardelli, S.; Battaglia, P.; Biviano, A.; Branchini, E.; Brescia, M.; Camera, S.; Cañas-Herrera, G.; Capobianco, V.; Carbone, C.; Carretero, J.; Castellano, M.; Castignani, G.; Cavuoti, S.; Chambers, K. C.; Cimatti, A.; Colodro-Conde, C.; Congedo, G.; Conversi, L.; Copin, Y.; Courbin, F.; Courtois, H. M.; Cropper, M.; Cuillandre, J.-C.; Degaudenzi, H.; De Lucia, G.; Dolding, C.; Dole, H.; Douspis, M.; Dubath, F.; Dupac, X.; Dusini, S.; Escoffier, S.; Farina, M.; Farinelli, R.; Ferriol, S.; Finelli, F.; Fourmanoit, N. et al.
Bibliographical reference
Astronomy and Astrophysics
Advertised on:
7
2026
Journal
Citations
17
Refereed citations
0
Description
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. ★ This paper is published on behalf of the Euclid Consortium.