Recursive formalism computes scattering-order-resolved photon escape probabilities in slab Thomson media, yielding exact mean scattering numbers like ⟨N⟩=2τ and eigenmode limits for high orders, verified by Monte Carlo.
Advection-Dominated Accretion: Underfed Black Holes and Neutron Stars
10 Pith papers cite this work. Polarity classification is still indexing.
abstract
We describe new optically thin solutions for rotating accretion flows around black holes and neutron stars. These solutions are advection dominated, so that most of the viscously dissipated energy is advected radially with the flow. We model the accreting gas as a two temperature plasma and include cooling by bremsstrahlung, synchrotron, and Comptonization. We obtain electron temperatures $T_e\sim 10^{8.5}-10^{10}$K. The new solutions are present only for mass accretion rates $\dot M$ less than a critical rate $\dot M_{crit}$ which we calculate as a function of radius $R$ and viscosity parameter $\alpha$. For $\dot M<\dot M_{crit}$ we show that there are three equilibrium branches of solutions. One of the branches corresponds to a cool optically thick flow which is the well-known thin disk solution of Shakura \& Sunyaev (1973). Another branch corresponds to a hot optically thin flow, discovered originally by Shapiro, Lightman \& Eardley (1976, SLE). This solution is thermally unstable. The third branch corresponds to our new advection-dominated solution. This solution is hotter and more optically thin than the SLE solution, but is viscously and thermally stable. It is related to the ion torus model of Rees et al. (1982) and may potentially explain the hard X-ray and $\gamma$-ray emission from X-ray binaries and active galactic nuclei.
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citation-polarity summary
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2026 10roles
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3D GRMHD simulations of accretion onto a JMN-1 horizonless singularity produce a magnetically arrested disk with an accretion rate of ~3e-6 Eddington matching M87* observations and EHT-consistent images, plus central brightness inside the shadow as a discriminant from black holes.
Machine learning on simulated images identifies that flux eruption events cause more diffuse, polarized, lower-flux millimeter emission with decreased Q-U loop rotation rate, achieving ~80% accuracy with random forests on summary statistics.
Self-consistent thermal regulation in circumbinary disks permits long-lived non-accretion phases that suppress binary feeding rates toward the Eddington limit while leaving optical/near-IR detectability intact.
Recoil kicks and binary interactions in AGN disks suppress EMRI formation except in young systems, predicting LISA rates of 1-30 per year dominated by low-mass AGNs.
External quadrupolar distortion imprints on orbital dynamics and accretion structure in thin disks around deformed compact objects, with the radiating region's outer edge tied to the radiation-to-gas pressure transition.
Radio precedes X-ray Compton luminosity by ~3 days in the rising hard state but lags by ~8 days in the decaying hard state of GX 339-4, with inner magnetic field strength estimated from accretion rate and truncation radius accounting for both.
VLA radio-selected LLAGN show 84% optical, 63% X-ray, and 13% infrared detection rates, with black holes ~0.7 dex smaller, accretion rates ~4.2 dex lower, and host galaxies ~0.3 dex lower in stellar mass with ~0.5 dex suppressed star formation than Swift-BAT AGN.
The paper reviews radio galaxy physics and outlines SKA-enabled studies of jet duty cycles, episodic activity, and dying sources.
citing papers explorer
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Photon Escape from Slab Thomson Media: A Scattering-order-resolved Recursive Formalism for Comptonization Applications
Recursive formalism computes scattering-order-resolved photon escape probabilities in slab Thomson media, yielding exact mean scattering numbers like ⟨N⟩=2τ and eigenmode limits for high orders, verified by Monte Carlo.
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GRMHD accretion beyond the black hole paradigm: Light from within the shadow
3D GRMHD simulations of accretion onto a JMN-1 horizonless singularity produce a magnetically arrested disk with an accretion rate of ~3e-6 Eddington matching M87* observations and EHT-consistent images, plus central brightness inside the shadow as a discriminant from black holes.
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Identifying Observational Signatures of Flux Eruption Events in Supermassive Black Hole Accretion Flows with Machine Learning
Machine learning on simulated images identifies that flux eruption events cause more diffuse, polarized, lower-flux millimeter emission with decreased Q-U loop rotation rate, achieving ~80% accuracy with random forests on summary statistics.
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Dynamics and detectability of long-lived non-accretion phases for massive black hole binaries in cold, thermally regulating disks
Self-consistent thermal regulation in circumbinary disks permits long-lived non-accretion phases that suppress binary feeding rates toward the Eddington limit while leaving optical/near-IR detectability intact.
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Recoil-regulated extreme mass-ratio inspirals in AGN disks
Recoil kicks and binary interactions in AGN disks suppress EMRI formation except in young systems, predicting LISA rates of 1-30 per year dominated by low-mass AGNs.
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Analytic thin disks and rings in a class of nonasymptotically flat static spacetimes
External quadrupolar distortion imprints on orbital dynamics and accretion structure in thin disks around deformed compact objects, with the radiating region's outer edge tied to the radiation-to-gas pressure transition.
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Radio-X-ray Time Lags in GX 339-4: Probing Magnetic Field Transport in Black Hole Accretion
Radio precedes X-ray Compton luminosity by ~3 days in the rising hard state but lags by ~8 days in the decaying hard state of GX 339-4, with inner magnetic field strength estimated from accretion rate and truncation radius accounting for both.
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Nuclear Activity and Host Galaxy Properties of Low-Luminosity AGN Identified from VLA Observations
VLA radio-selected LLAGN show 84% optical, 63% X-ray, and 13% infrared detection rates, with black holes ~0.7 dex smaller, accretion rates ~4.2 dex lower, and host galaxies ~0.3 dex lower in stellar mass with ~0.5 dex suppressed star formation than Swift-BAT AGN.
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Radio Galaxies and Jet Duty Cycles
The paper reviews radio galaxy physics and outlines SKA-enabled studies of jet duty cycles, episodic activity, and dying sources.
- Polarization Signatures of Inspiraling Hotspots around Kerr Black Holes