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تسجيل مستخدم جديدFeedback by supermassive black holes in galaxy evolution: impacts of accretion and outflows on the star formation rate
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We describe a physical model of the outflows produced as a result of gas accretion onto a black hole, and the resultant changes to star formation rates and efficiencies in galaxies, using the Radio-SAGE semi-analytic galaxy formation model. We show that the ratio of outflow rate to SFR of galaxies is mainly driven by black hole mass and virial halo mass, and show that the SFR is higher than the outflow rate at low black hole masses. The model consistently reproduces the observed evolution of star formation rate density from z = 6 to z = 0, as well as the trend of the stellar mass - halo mass relations. We show the characteristic growth of massive galaxies influenced by AGN feedback at different redshifts. We find feedback to be prevalent in the most massive galaxy halos, inhibiting the cooling catastrophe.
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We present a new suite of hydrodynamical simulations and use it to study, in detail, black hole and galaxy properties. The high time, spatial and mass resolution, and realistic orbits and mass ratios, down to 1:6 and 1:10, enable us to meaningfully c
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It is well established that the properties of supermassive black holes and their host galaxies are correlated through scaling relations. While hydrodynamical cosmological simulations have begun to account for the co-evolution of BHs and galaxies, the
y typically have neglected the BH spin, even though it may play an important role in modulating the growth and feedback of BHs. Here we introduce a new sub-grid model for the BH spin evolution in the moving-mesh code {small AREPO} in order to improve the physical faithfulness of the BH modelling in galaxy formation simulations. We account for several different channels of spin evolution, in particular gas accretion through a Shakura-Sunyaev $alpha$-disc, chaotic accretion, and BH mergers. For BH feedback, we extend the IllustrisTNG model, which considers two different BH feedback modes, a thermal quasar mode for high accretion states and a kinetic mode for low Eddington ratios, with a self-consistent accounting of spin-dependent radiative efficiencies and thus feedback strength. We find that BHs with mass $M_{rm{bh}}lesssim 10^{8}, {rm M}_odot$ reach high spin values as they typically evolve in the coherent gas accretion regime. On the other hand, BHs with mass $M_{rm{bh}}gtrsim 10^{8}, {rm M}_odot$ have lower spins as BH mergers become more frequent, and their accretion discs fragment due to self-gravity, inducing chaotic accretion. We also explore the hypothesis that the transition between the quasar and kinetic feedback modes is mediated by the accretion mode of the BH disc itself, i.e.~the kinetic feedback mode is activated when the disc enters the self-gravity regime. We find excellent agreement between the galaxy and BH populations for this approach and the fiducial TNG model with no spin evolution. Furthermore, our new approach alleviates a tension in the galaxy morphology -- colour relation of the original TNG model.
The next generation of electromagnetic and gravitational wave observatories will open unprecedented windows to the birth of the first supermassive black holes. This has the potential to reveal their origin and growth in the first billion years, as we
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Large-scale, broad outflows are common in active galaxies. In systems where star formation coexists with an AGN, it is unclear yet the role that both play on driving the outflows. In this work we present three-dimensional radiative-cooling MHD simula
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