Roberta Tripodi, Nicholas S. Martis, Vladan Markov, Maruša Bradač, Fabio Di Mascia, Vieri Cammelli, Francesco D’Eugenio, Chris J. Willott, Mirko Curti, Maulik Bhatt, S. Gallerani, Gregor Rihtaršič, Jasbir Singh, Gaia Gaspar, Anishya Harshan, Jon Judež, Rosa M. Mérida, G. Desprez, Marcin Sawicki, Ilias Goovaerts, Adam Muzzin, Gaël Noirot, Ghassan T. E. Sarrouh, Roberto Abraham, Yoshihisa Asada, Gabriel Brammer, Vicente Estrada-Carpenter, Giordano Felicioni, Seiji Fujimoto, Kartheik G. Iyer, Lamiya Mowla, Victoria Strait
Little red dots (LRDs) are a high redshift galaxy population. Despite their high number densities, their nature is still uncertain. Here we present CANUCS-LRD-z8.6, a spectroscopically confirmed little red dot at a spectroscopic redshift of zspec = 8.6319, hosting an active galactic nucleus. Its spectrum exhibits broad Hβλ4863 Å emission, high-ionization lines (C iv, N iv]), high electron temperature, which are indicative of active galactic nucleus activity, and low metallicity (Z < 0.1−0.2Z⊙). The inferred black hole mass, $${M}_{{{{\rm{BH}}}}}=1.{0}_{-0.4}^{+0.6}\times 1{0}^{8}\,{{{{\rm{M}}}}}_{\odot }$$ , poses strong constraints on current black hole formation models and simulations. Additionally, its black hole is over-massive relative to its host, deviating from local MBH − M* relations, suggesting an early, rapid black hole growth preceding that of its galaxy. CANUCS-LRD-z8.6 may represent an evolutionary link between early massive black holes and the luminous quasars observed at z = 6. Little Red Dots (LRDs) are a high-redshift galaxy population with unclear nature. Here, authors show CANUCS-LRD-z8.6, a spectroscopically confirmed LRD, hosting an active galactic nucleus, and its properties provide insights for early black hole and galaxy formation.