Cold flows and the first quasars

Understand

Observations of the most distant bright quasars imply that billion solar mass supermassive black holes (SMBH) have to be assembled within the first eight hundred million years.

• Under our standard galaxy formation scenario such fast growth implies large gas densities providing sustained accretion at critical or supercritical rates onto an initial black hole seed.
• It has been a long standing question whether and how such high black hole accretion rates can be achieved and sustained at the centers of early galaxies.
• Here we use our new cosmological hydrodynamic simulation (MassiveBlack) covering a volume (0.75 \Gpc)^3 appropriate for studying the rare first quasars to show that steady high density cold gas flows responsible for assembling the first galaxies produce the high gas densities that lead to sustained critical accretion rates and hence rapid growth commensurate with the existence of ~10^9 solar mass black holes as early as z~7.