Baryon cycles in the biggest galaxies

Donahue, M.; Voit, G. Mark

doi:10.1016/j.physrep.2022.04.005

Cited by 67 publications

(48 citation statements)

References 622 publications

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“…This is consistent with the results obtained here and by Daly (2009a) that indicated a small value and range of values of total outflow energy relative to black hole dynamical mass: Log(E T /M dyn ) ≃ −2.5 ± 0.3 for the 100 FRII sources studied here (see sections 3 and 4.3). The value obtained here is consistent with that obtained by Daly (2009a) and that with obtained with a different method applied to different types of sources by Donahue & Voit (2022), who find Log(E T /M dyn ) ≃ −2.3 ± 0.5 for a sample of low redshift sources. The small value and restricted range of values of Log(E T /M dyn ) could suggest that this is a fundamental property of the primary process responsible for producing the dual collimated outflows.…”

Section: Discussionsupporting

confidence: 92%

“…1 from Daly 2009a). These results are consistent with the empirically determined value of about −2.3±0.5 obtained by Donahue & Voit (2022) (see their Fig. 20) based on empirical studies of the energy input required to heat and lift the circumgalactic medium and shut off accretion for a sample of relatively low redshift sources.…”

Section: Total Outflow Energy Relative To Spin Mass-energy and Relati...supporting

confidence: 91%

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Robust supermassive black hole spin mass-energy characteristics: a new method and results

Daly

2022

Monthly Notices of the Royal Astronomical Society

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The rotational properties of astrophysical black holes are fundamental quantities that characterization the black holes. A new method to empirically determine the spin mass-energy characteristics of astrophysical black holes is presented and applied here. Results are obtained for a sample of 100 supermassive black holes with collimated dual outflows and redshifts between about zero and two. An analysis indicates that about two-thirds of the black holes are maximally spinning, while one-third have a broad distribution of spin values; it is shown that the same distributions describe the quantity $\rm {(M_{rot}/M_{irr})}$. The new method is applied to obtain the black hole spin mass-energy, $\rm {M_{spin}}$, available for extraction relative to: the maximum possible value, the irreducible black hole mass, and the total black hole mass, $\rm {M_{dyn}}$. The total energy removed from the black hole system and deposited into the circumgalactic medium via dual outflows over the entire outflow lifetime of the source, $\rm {E_T}$, is studied relative to $\rm {M_{dyn}}$ and relative to the spin energy available per black hole, $\rm {E_{spin}/(M_{\odot }c^2)}$. The mean value of $\rm {Log(E_T/M_{dyn})}$ is about ( − 2.47 ± 0.27). Several explanations of this and related results are discussed. For example, the energy input to the ambient gas from the outflow could turn-off the accretion, or the impact of the black hole mass loss on the system could destabilize and terminate the outflow. The small values and restricted range of values of $\rm {Log(E_T/M_{dyn})}$ and $\rm {Log(E_T/E_{spin})}$ could suggest that these are fundamental properties of the primary process responsible for producing the dual collimated outflows.

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Section: Discussionsupporting

confidence: 92%

Section: Total Outflow Energy Relative To Spin Mass-energy and Relati...supporting

confidence: 91%

Robust supermassive black hole spin mass-energy characteristics: a new method and results

Daly

2022

Monthly Notices of the Royal Astronomical Society

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“…However, there -as well as in the CGM -the origin of this molecular gas is unknown (Veilleux et al 2020). In the context of the ICM, the ∼10 4 K gas is thought to predominantly originate from thermal instability, i.e., to form insitu (Sharma et al 2012;McCourt et al 2012;Donahue & Voit 2022) and potentially 'shatter' during the cooling process (McCourt et al 2018). Our results suggest that a similar process might be responsible to form a colder phase leading to a 'fog' of 1000 K gas.…”

Section: Discussionmentioning

confidence: 72%

Molecular Shattering

Farber¹,

Grönke²

2022

Preprint

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Recent observations suggest galaxies may ubiquitously host a molecular component to their multiphase circumgalactic medium (CGM). However, the structure and kinematics of the molecular CGM remains understudied theoretically and largely unconstrained observationally. Recent work suggests molecular gas clouds with efficient cooling survive acceleration in hot winds similar to atomic clouds. Yet the pressure-driven fragmentation of molecular clouds when subjected to external shocks or undergoing cooling remains unstudied. We perform radiative, inviscid hydrodynamics simulations of clouds perturbed out of pressure equilibrium to explore the process of hydrodynamic fragmentation to molecular temperatures. We find molecular clouds larger than a critical size can shatter into a mist of tiny droplets, with the critical size deviating significantly from the atomic case. We find that cold clouds shatter only if the sound crossing time exceeds the local maximum of the cooling time ∼8000 K. Moreover, we find evidence for a universal mechanism to 'shatter' cold clouds into a 'mist' of tiny droplets as a result of rotational fragmentation -a process we dub 'splintering.' Our results have implications for resolving the molecular phase of the CGM in observations and cosmological simulations.

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“…Many models of the gas surrounding galaxies were developed using more massive halos than the L * scale we explore in this work. In galaxy groups and clusters, observations of X-ray emission and the Sunyaev-Zel'dovich (SZ) effect, which trace predominantly hot gas, suggest hydrostatic equilibrium is an accurate and descriptive model, with 15% of the pressure support provided by non-thermal pressures (see the recent review and references therein by Donahue & Voit 2022). The deeper gravitational potential well of massive halos reduces the effect of feedback, which may act to damp turbulence.…”

Section: Global Forces and Galaxy Evolution Modelsmentioning

confidence: 99%

Figuring Out Gas & Galaxies In Enzo (FOGGIE) VI: The Circumgalactic Medium of $L^*$ Galaxies is Supported in an Emergent, Non-Hydrostatic Equilibrium

Lochhaas¹,

Tumlinson²,

Peeples³

et al. 2022

Preprint

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The circumgalactic medium (CGM) is often assumed to exist in or near hydrostatic equilibrium with the regulation of accretion and the effects of feedback treated as perturbations to a stable balance between gravity and thermal pressure. We investigate global hydrostatic equilibrium in the CGM using four highly-resolved L * galaxies from the Figuring Out Gas & Galaxies In Enzo (FOGGIE) project. The FOGGIE simulations were specifically targeted at fine spatial and mass resolution in the CGM (∆x 1 kpc h −1 and M 200M ). We develop a new analysis framework that calculates the forces provided by thermal pressure gradients, turbulent pressure gradients, ram pressure gradients of large-scale radial bulk flows, centrifugal rotation, and gravity acting on the gas in the CGM. Thermal and turbulent pressure gradients vary strongly on scales of 5 kpc throughout the CGM. Thermal pressure gradients provide the main supporting force only beyond ∼ 0.25R 200 , or ∼ 50 kpc at z = 0. Within ∼ 0.25R 200 , turbulent pressure gradients and rotational support provide stronger forces than thermal pressure. More generally, we find that global equilibrium models are neither appropriate nor predictive for the small scales probed by absorption line observations of the CGM. Local conditions generally cannot be derived from a global equilibrium, but an emergent equilibrium balancing radially inward and outward forces is obtained when averaging over large scales in space and time. Approximate hydrostatic equilibrium holds only at large distances from galaxies even when averaging out small-scale variations.

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Baryon cycles in the biggest galaxies

Cited by 67 publications

References 622 publications

Robust supermassive black hole spin mass-energy characteristics: a new method and results

Robust supermassive black hole spin mass-energy characteristics: a new method and results

Molecular Shattering

Figuring Out Gas & Galaxies In Enzo (FOGGIE) VI: The Circumgalactic Medium of $L^*$ Galaxies is Supported in an Emergent, Non-Hydrostatic Equilibrium

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