X-ray investigation of possible super-Eddington accretion in a radio quasar at z = 6.1

How the supermassive black holes (SMBHs) we observe in the early Universe formed and grew to the observed sizes in such a short period of time is still not clear. While the formation of already massive black hole seeds may help explain the most extreme cases, super-Eddington accretion is likely required to account for their observed multi-wavelength properties. In particular, recent studies suggest that the strong upper-limits on the X-ray emission of the z>4 BHs discovered with JWST can be naturally explained in the context of super-Eddington accretion.