UNCOVER: A NIRSpec Identification of a Broad Line AGN at z = 8.50

Understand

Deep observations with JWST have revealed an emerging population of red point-like sources that could provide a link between the postulated supermassive black hole seeds and observed quasars.

• In this work we present a JWST/NIRSpec spectrum from the JWST Cycle 1 UNCOVER Treasury survey, of a massive accreting black hole at $z=8.50$, displaying a clear broad-line component as inferred from the H$\beta$ line with FWHM = $3439\pm413$ km s$^{-1}$, typical of the broad line region of an active galactic nucleus (AGN).
• The AGN nature of this object is further supported by high ionization, as inferred from emission lines, and a point-source morphology.
• We compute the black hole mass of log$_{10}(M_{\rm BH}/M_\odot)=8.17\pm0.42$, and a bolometric luminosity of $L_{\rm bol}\sim6.6\times10^{45}$ erg s$^{-1}$.