A direct black-hole mass measurement in a little red dot at high redshift (opens in new tab)

Recent discoveries of faint active galactic nuclei (AGN) at the redshift frontier have revealed a plethora of broad Hα emitters with optically red continua, named little red dots (LRDs)1, which comprise 15–30% of the high-redshift broad-line AGN population2. Owing to their peculiar properties3–6, modelling LRDs with standard AGN scenarios has proven challenging. In particular, the validity of single-epoch virial mass estimates in determining the black-hole masses of LRDs has been called into ...