The Structure of Radiatively Inefficient Black Hole Accretion Flows

White, Christopher J.; Quataert, Eliot; Gammie, Charles F.

doi:10.3847/1538-4357/ab718e

Cited by 38 publications

(36 citation statements)

References 46 publications

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“…We have also run sample MAD and SANE simulations to long durations, similar to what was done by Narayan et al (2012) and White et al (2020b). Averaged properties of those simulations over various time intervals are listed in Table 2 and Table 3.…”

Section: Long Duration Runs and Inflow Equilibriummentioning

confidence: 99%

A parameter survey of Sgr A* radiative models from GRMHD simulations with self-consistent electron heating

Dexter

Jiménez-Rosales

Ressler

et al. 2020

Monthly Notices of the Royal Astronomical Society

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The Galactic center black hole candidate Sgr A* is the best target for studies of lowluminosity accretion physics, including with near-infrared and submillimeter wavelength long baseline interferometry experiments. Here we compare images and spectra generated from a parameter survey of general relativistic MHD simulations to a set of radio to near-infrared observations of Sgr A*. Our models span the limits of weak and strong magnetization and use a range of sub-grid prescriptions for electron heating. We find two classes of scenarios can explain the broad shape of the submillimeter spectral peak and the highly variable near-infrared flaring emission. Weakly magnetized "disk-jet" models where most of the emission is produced near the jet wall, consistent with past work, as well as strongly magnetized (magnetically arrested disk) models where hot electrons are present everywhere. Disk-jet models are strongly depolarized at submillimeter wavelengths as a result of strong Faraday rotation, inconsistent with observations of Sgr A*. We instead favor the strongly magnetized models, which provide a good description of the median and highly variable linear polarization signal. The same models can also explain the observed mean Faraday rotation measure and potentially the polarization signals seen recently in Sgr A* near-infrared flares.

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Section: Long Duration Runs and Inflow Equilibriummentioning

confidence: 99%

A parameter survey of Sgr A* radiative models from GRMHD simulations with self-consistent electron heating

Dexter

Jiménez-Rosales

Ressler

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…We analyse the accretion rate data from five different simulations of ADAFs, which were initiated using different initial conditions and were performed using different GRMHD codes. While we performed simulation D in the interest of this work, simulations A, B, and C were taken from White et al (2020), while simulation R comes from Narayan et al (2012). In this section, we briefly describe the numerical set-ups of each simulation and discuss their key differences.…”

Section: E S C R I P T I O N O F S I M U L At I O N Smentioning

confidence: 99%

“…Just the difference in causes a much more spherical distribution of mass in simulation C compared to simulations A and B that present a more standard disc picture, with high density near the equatorial region and low density close to the polar region. Further details of these simulations are provided in White et al (2020).…”

Section: Simulations a B And Cmentioning

confidence: 99%

“…The GRMHD simulations analysed in this work are notable for their extremely long time duration, which makes it possible to probe a wider frequency range of broad-band variability. However, a drawback of the fast timescales associated with ADAFs is that simulations of them can be particularly sensitive to the initial conditions used (White, Quataert & Gammie 2020); for this reason, we analyse simulations with different initial conditions, which can help discern the robustness of the propagating fluctuations in these flows.…”

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confidence: 99%

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Looking for the underlying cause of black hole X-ray variability in GRMHD simulations

Bollimpalli

Mahmoud

Done

et al. 2020

Monthly Notices of the Royal Astronomical Society

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ABSTRACT Long-term observations have shown that black hole X-ray binaries exhibit strong, aperiodic variability on time-scales of a few milliseconds to seconds. The observed light curves display various characteristic features like a lognormal distribution of flux and a linear rms–flux relation, which indicate that the underlying variability process is stochastic in nature. It is also thought to be intrinsic to accretion. This variability has been modelled as inward propagating fluctuations of mass accretion rate, although the physical process driving the fluctuations remains puzzling. In this work, we analyse five exceptionally long-duration general relativistic magnetohydrodynamic (GRMHD) simulations of optically thin, geometrically thick, black hole accretion flows to look for hints of propagating fluctuations in the simulation data. We find that the accretion profiles from these simulations do show evidence for inward propagating fluctuations below the viscous frequency by featuring strong radial coherence and positive time lags when comparing smaller to larger radii, although these time lags are generally shorter than the viscous time-scale and are frequency-independent. Our simulations also support the notion that the fluctuations in $\dot{M}$ build up in a multiplicative manner, as the simulations exhibit linear rms–mass flux relations, as well as lognormal distributions of their mass fluxes. When combining the mass fluxes from the simulations with an assumed emissivity profile, we additionally find broad agreement with observed power spectra and time lags, including a recovery of the frequency dependency of the time lags.

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“…Theories indicate that LLAGN are characterized by a low accretion rate ( ṁ) and/or low radiative efficiency (Ho 1999;Panessa et al 2007). In models of radiatively inefficient accretion flows (RIAFs; Narayan & Yi 1994Yuan, Bu & Wu 2012a;Yuan, Wu & Bu 2012b;White, Quataert & Gammie 2020), the kinetic energy is either advected with the gas into the SMBH or channelled into an outflow. The magnetic field combined with 'puffed-up' geometrically thick structures could provide a plausible mechanism for collimating axial outflows, accounting for a large fraction of observed jets in LLAGN (Maoz 2007;Mezcua & Prieto 2014).…”

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confidence: 99%

LeMMINGs III. The e-MERLIN legacy survey of the Palomar sample: exploring the origin of nuclear radio emission in active and inactive galaxies through the [O iii] – radio connection

Baldi

Williams

Beswick

et al. 2021

Monthly Notices of the Royal Astronomical Society

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What determines the nuclear radio emission in local galaxies? To address this question, we combine optical [O iii] line emission, robust black hole (BH) mass estimates, and high-resolution e-MERLIN 1.5-GHz data, from the LeMMINGs survey, of a statistically complete sample of 280 nearby optically active (LINER and Seyfert) and inactive [H ii and absorption line galaxies (ALGs)] galaxies. Using [O iii] luminosity ($L_{\rm [O\, \small {III}]}$) as a proxy for the accretion power, local galaxies follow distinct sequences in the optical–radio planes of BH activity, which suggest different origins of the nuclear radio emission for the optical classes. The 1.5-GHz radio luminosity of their parsec-scale cores (Lcore) is found to scale with BH mass (MBH) and [O iii] luminosity. Below MBH ∼ 106.5 M⊙, stellar processes from non-jetted H ii galaxies dominate with $L_{\rm core} \propto M_{\rm BH}^{0.61\pm 0.33}$ and $L_{\rm core} \propto L_{\rm [O\, \small {III}]}^{0.79\pm 0.30}$. Above MBH ∼ 106.5 M⊙, accretion-driven processes dominate with $L_{\rm core} \propto M_{\rm BH}^{1.5-1.65}$ and $L_{\rm core} \propto L_{\rm [O\, \small {III}]}^{0.99-1.31}$ for active galaxies: radio-quiet/loud LINERs, Seyferts, and jetted H ii galaxies always display (although low) signatures of radio-emitting BH activity, with $L_{\rm 1.5\, GHz}\gtrsim 10^{19.8}$ W Hz−1 and MBH ≳ 107 M⊙, on a broad range of Eddington-scaled accretion rates ($\dot{m}$). Radio-quiet and radio-loud LINERs are powered by low-$\dot{m}$ discs launching sub-relativistic and relativistic jets, respectively. Low-power slow jets and disc/corona winds from moderately high to high-$\dot{m}$ discs account for the compact and edge-brightened jets of Seyferts, respectively. Jetted H ii galaxies may host weakly active BHs. Fuel-starved BHs and recurrent activity account for ALG properties. In conclusion, specific accretion–ejection states of active BHs determine the radio production and the optical classification of local active galaxies.

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The Structure of Radiatively Inefficient Black Hole Accretion Flows

Cited by 38 publications

References 46 publications

A parameter survey of Sgr A* radiative models from GRMHD simulations with self-consistent electron heating

A parameter survey of Sgr A* radiative models from GRMHD simulations with self-consistent electron heating

Looking for the underlying cause of black hole X-ray variability in GRMHD simulations

LeMMINGs III. The e-MERLIN legacy survey of the Palomar sample: exploring the origin of nuclear radio emission in active and inactive galaxies through the [O iii] – radio connection

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