2026ApJ...998..175M

We report the detection of Lyα in CANUCS-LRD-z8.6, a recently discovered active galactic nucleus (AGN) at z = 8.63 by R. Tripodi et al. (), in new NIRSpec/MSA G140H/F070LP observations. We detect broad Lyα emission (FWHM = 1540 ± 260 km s^–1) near the systemic velocity, which suggests a large ionizing bubble, considering that the Universe is almost fully neutral at the redshift. Through Lyα line-shape modeling assuming a Strömgren sphere, we find a large bubble radius, R_b = $1.{5}_{-0.2}^{+0.3}$ pMpc, and a moderately high Lyα escape fraction, f_esc = 11% ± 3%. The intrinsic line width is inferred to be broad (2200 ± 280 km s^–1), likely originating in the broad-line region. Existing data indicate that CANUCS-LRD-z8.6 is within a mild overdensity, δ = $1.{8}_{-0.6}^{+3.0}$, suggesting that other galaxies in its proximity might have contributed to the formation of the bubble. The high N IV]_λ1488/C IV_λ1548 and N IV]_λ1488/O III]_λ1661 line ratios measured in existing NIRSpec/PRISM data indicate nitrogen enrichment in this metal-poor, low-luminosity AGN. The spectroscopic features are overall similar to those of other nitrogen-rich galaxies discovered in the literature, such as GN-z11 and GHZ2/GLASSz12. This suggests that CANUCS-LRD-z8.6 may represent one of the evolutionary phases of those nitrogen-rich galaxies.