Bridging Scales in Black Hole Accretion and Feedback: Relativistic Jet linking the Horizon to the Host Galaxy

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Hauptverfasser: Cho, Hyerin, Prather, Ben S., Narayan, Ramesh, Su, Kung-Yi, Natarajan, Priyamvada
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Veröffentlicht: 2025
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author Cho, Hyerin
Prather, Ben S.
Narayan, Ramesh
Su, Kung-Yi
Natarajan, Priyamvada
author_facet Cho, Hyerin
Prather, Ben S.
Narayan, Ramesh
Su, Kung-Yi
Natarajan, Priyamvada
contents Simulating black hole (BH) accretion and feedback from the horizon to galactic scales is extremely challenging, as it involves a vast range of scales. Recently, our multizone method has successfully achieved global dynamical steady-states of hot accretion flows in three-dimensional general relativistic magnetohydrodynamic (GRMHD) simulations by tracking the bidirectional interaction between a non-spinning BH and its host galaxy. In this paper, we present technical improvements to the method and apply it to spin $a_*=0.9$ BHs, which power relativistic jets. We first test the new multizone set-up with a smaller Bondi radius, $R_B\approx400\,r_g$, where $r_g$ is the gravitational radius. The strongly magnetized accretion launches a relativistic jet with an intermediate feedback efficiency $η\sim30\,\%$, in between that of a prograde ($η\sim100\,\%$) and retrograde ($η\sim 10\,\%$) torus. Interestingly, both prograde and retrograde simulations also eventually converge to the same intermediate efficiency when evolved long enough, as accumulated magnetic fields remove gas rotation. We then extend strongly magnetized simulations to larger Bondi radii, $R_B\approx 2\times10^3,~2\times 10^4,~2\times 10^5\,r_g$. We find that the BH accretion rate $\dot{M}$ is suppressed with respect to the Bondi rate $\dot{M}_B$ as $\dot{M}/\dot{M}_B\propto R_B^{-1/2}$. However, despite some variability, the time-averaged feedback efficiency is $η\sim30\,\%$, independent of $R_B$. This suggests that BH feedback efficiency in hot accretion flows is mainly governed by the BH spin ($a_*$) rather than by the galactic properties ($R_B$). From these first-principles simulations, we provide a feedback subgrid prescription for cosmological simulations: $\dot{E}_{\rm fb}=2\times10^{-3}[R_B/(2\times10^5\,r_g)]^{-1/2}\dot{M}_Bc^2$ for BH spin $a_*=0.9$.
format Preprint
id arxiv_https___arxiv_org_abs_2507_17818
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Bridging Scales in Black Hole Accretion and Feedback: Relativistic Jet linking the Horizon to the Host Galaxy
Cho, Hyerin
Prather, Ben S.
Narayan, Ramesh
Su, Kung-Yi
Natarajan, Priyamvada
High Energy Astrophysical Phenomena
Astrophysics of Galaxies
Simulating black hole (BH) accretion and feedback from the horizon to galactic scales is extremely challenging, as it involves a vast range of scales. Recently, our multizone method has successfully achieved global dynamical steady-states of hot accretion flows in three-dimensional general relativistic magnetohydrodynamic (GRMHD) simulations by tracking the bidirectional interaction between a non-spinning BH and its host galaxy. In this paper, we present technical improvements to the method and apply it to spin $a_*=0.9$ BHs, which power relativistic jets. We first test the new multizone set-up with a smaller Bondi radius, $R_B\approx400\,r_g$, where $r_g$ is the gravitational radius. The strongly magnetized accretion launches a relativistic jet with an intermediate feedback efficiency $η\sim30\,\%$, in between that of a prograde ($η\sim100\,\%$) and retrograde ($η\sim 10\,\%$) torus. Interestingly, both prograde and retrograde simulations also eventually converge to the same intermediate efficiency when evolved long enough, as accumulated magnetic fields remove gas rotation. We then extend strongly magnetized simulations to larger Bondi radii, $R_B\approx 2\times10^3,~2\times 10^4,~2\times 10^5\,r_g$. We find that the BH accretion rate $\dot{M}$ is suppressed with respect to the Bondi rate $\dot{M}_B$ as $\dot{M}/\dot{M}_B\propto R_B^{-1/2}$. However, despite some variability, the time-averaged feedback efficiency is $η\sim30\,\%$, independent of $R_B$. This suggests that BH feedback efficiency in hot accretion flows is mainly governed by the BH spin ($a_*$) rather than by the galactic properties ($R_B$). From these first-principles simulations, we provide a feedback subgrid prescription for cosmological simulations: $\dot{E}_{\rm fb}=2\times10^{-3}[R_B/(2\times10^5\,r_g)]^{-1/2}\dot{M}_Bc^2$ for BH spin $a_*=0.9$.
title Bridging Scales in Black Hole Accretion and Feedback: Relativistic Jet linking the Horizon to the Host Galaxy
topic High Energy Astrophysical Phenomena
Astrophysics of Galaxies
url https://arxiv.org/abs/2507.17818