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ABSTRACT In the absence of supplementary heat, the radiative cooling of halo gas around massive galaxies (Milky Way mass and above) leads to an excess of cold gas or stars beyond observed levels. Active galactic nucleus jet-induced heating is likely essential, but the specific properties of the jets remain unclear. Our previous work concludes from simulations of a halo with $$10^{14} \,\mathrm{ M}_\odot$$ that a successful jet model should have an energy flux comparable to the free-fall energy flux at the cooling radius and should inflate a sufficiently wide cocoon with a long enough cooling time. In this paper, we investigate three jet modes with constant fluxes satisfying the criteria, including high-temperature thermal jets, cosmic ray (CR)-dominant jets, and widely precessing kinetic jets in $$10^{12}-10^{15}\, {\rm M}_{\odot }$$ haloes using high-resolution, non-cosmological magnetohydrodynamic simulations with the FIRE-2 (Feedback In Realistic Environments) stellar feedback model, conduction, and viscosity. We find that scaling the jet energy according to the free-fall energy at the cooling radius can successfully suppress the cooling flows and quench galaxies without violating observational constraints. On the contrary, if we scale the energy flux based on the total cooling rate within the cooling radius, strong interstellar medium cooling dominates this scaling, resulting in a jet flux exceeding what is needed. Among the three jet types, the CR-dominant jet is most effective in suppressing cooling flows across all surveyed halo masses due to enhanced CR pressure support. We confirm that the criteria for a successful jet model work across a wider range, encompassing halo masses of $$10^{12}-10^{15} {\rm M_\odot }$$.
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Self-regulation of high-redshift black hole accretion via jets: challenges for SMBH formation
ABSTRACT 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 $${\rm M_\odot }$$ BH in a constant density environment regulated by AGN jets, we expand the initial BH mass range from 1 to $$10^4\, {\rm M_\odot }$$ 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 $$10^4 \, {\rm M_\odot }$$. 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 ($$\gt 10^6 \, {\rm M_\odot }$$) within 1 Gyr entirely by accreting gas from an atomic-cooling halo, the jet energy feedback efficiency must be $$\lesssim 10^{-4} \dot{M}_{\rm BH} c^2$$ even if the seed BH mass is $$10^4 \, {\rm M_\odot }$$.
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- Award ID(s):
- 2006176
- PAR ID:
- 10575248
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Monthly Notices of the Royal Astronomical Society
- Volume:
- 538
- Issue:
- 1
- ISSN:
- 0035-8711
- Format(s):
- Medium: X Size: p. 11-30
- Size(s):
- p. 11-30
- Sponsoring Org:
- National Science Foundation
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