Self-regulation of high-redshift black hole accretion via jets: Challenges for SMBH formation

The early growth of black holes (BHs) in atomic-cooling haloes is likely influenced by feedback on the surrounding gas. While the effects of radiative feedback are well-documented, mechanical feedback, particularly from active galactic nucleus (AGN) jets, has been comparatively less explored. Building on our previous work that examined the growth of a 100 M BH in a constant density environment regulated by AGN jets, we expand the initial BH mass range from 1 to 104 M and adopt a more realistic density profile for atomic-cooling haloes. We reaffirm the validity of our analytic models for jet cocoon propagation and feedback regulation. We identify several critical radii – namely, the terminal radius of jet cocoon propagation, the isotropization radius of the jet cocoon, and the core radius of the atomic-cooling halo – that are crucial in determining BH growth given specific gas properties and jet feedback parameters. In a significant portion of the parameter space, our findings show that jet feedback substantially disrupts the halo’s core during the initial feedback episode, preventing BH growth beyond 104 M. Conversely, conditions characterized by low jet velocities and high gas densities enable sustained BH growth over extended periods. We provide a prediction for the BH mass growth as a function of time and feedback parameters. We found that, to form a supermassive BH (> 106 M) within 1 Gyr entirely by accreting gas from an atomic-cooling halo, the jet energy feedback efficiency must be 10−4M˙ BHc2 even if the seed BH mass is 104 M.