Self-consistent spherical accretion simulations show cooling-enhanced growth of PBHs with radiative efficiency ~10^{-2} in the bremsstrahlung regime, yielding a critical seed mass of ~10^{-16} M_sun to consume a solar-mass star in a Hubble time.
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Revisiting the Unified Model of Active Galactic Nuclei
25 Pith papers cite this work, alongside 736 external citations. Polarity classification is still indexing.
25
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736
external citations · Pith
abstract
This review describes recent developments related to the unified model of active galactic nuclei (AGN). It focuses on new ideas about the origin and properties of the central obscurer (torus), and the connection with its surrounding. The review does not address radio unification. AGN tori must be clumpy but the uncertainties about their properties are still large. Todays most promising models involve disk winds of various types and hydrodynamical simulations that link the large scale galactic disk to the inner accretion flow. IR studies greatly improved the understanding of the spectral energy distribution of AGNs but they are hindered by various selection effects. X-ray samples are more complete. A basic relationship which is still unexplained is the dependence of the torus covering factor on luminosity. There is also much confusion regarding "real type-II AGNs" that do not fit into a simple unification scheme. The most impressive recent results are due to IR interferometry, which is not in accord with most torus models, and the accurate mapping of central ionization cones. AGN unification may not apply to merging systems and is possibly restricted to secularly evolving galaxies.
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Spectroscopic study of 11 LRDs at z~4 finds AGN origin for optical emission via broad Hα correlations and introduces a clumpy envelope model with growth timescales of 10^5-10^7 years.
New publicly available X-ray table models RXToPo and RXagn1 with realistic AGN geometries (torus, polar cone, disk, BLR) generated via RefleX and tested on NGC 424.
Multi-dimensional simulations show that the parameter space for shocks in non-dissipative transonic sub-Keplerian accretion flows is substantially larger than the analytic prediction, with dynamic boundary layers producing outflows.
XRISM observation decomposes the Fe Kα line in Cygnus A into broad (3400 km/s, 0.1-0.17 pc) and narrow (440 km/s, 6-10 pc) Keplerian components attributed to the broad line region and torus.
Lya nebulae around unobscured quasars are more extended, asymmetric, and show steeper velocity dispersion declines than those around obscured quasars, supporting an evolutionary AGN model at cosmic noon.
High-resolution GRMHD simulations show that tearing of tilted accretion disks around rapidly spinning supermassive black holes drives order-of-magnitude variability in continuum and broad-line luminosities on months-to-years timescales, explaining changing-look AGN.
Requiring thermal stability and single-valuedness in the thin-disk Ṁ-Σ plane produces a viscosity law α(X) with X = P_gas/P_rad that eliminates the radiation-pressure dominated instability while preserving the effective-temperature profile.
Simulations demonstrate that a retrograde IMBH with mass ratio ~0.67 to the disc mass fragments a stellar disc into inner, misaligned, and outer components within 10-20 Myr.
IFU spectroscopy of NGC 6552 reveals decoupled ionized gas kinematics and excitation, with outflow energetics consistent with multi-phase outflow models.
Semi-analytical models show AGN disks produce repeated BBH mergers with a high-mass tail beyond the pair-instability gap, more efficiently at low viscosity, with spin and mass-ratio signatures that can match events like GW190521.
Disk reflection from a compact lamp-post corona explains the X-ray polarization and spectra of NGC 4151.
3D hydro simulations show that TDE outflow interactions with a broken power-law CNM can reproduce the range of observed radio light curves via early flares inside the Bondi radius and possible late rebrightenings outside it.
CL-AGN host galaxies exhibit a 29% merger fraction (about 2x higher than non-CL-AGN controls) with morphology indicating modest disturbances, based on non-parametric metrics and visual inspection of DESI images.
Using ray-tracing simulations and simulation-based inference, the authors construct an AGN population that reproduces the cosmic X-ray background, number counts, and absorption properties, deriving an intrinsic Compton-thick fraction of 40±3%.
JWST spectroscopy reveals radio jets in nearby AGN drive multiphase ISM turbulence and shock-dominated H2 excitation both along and perpendicular to the jet direction.
NOEMA CO(2-1) data show a nuclear molecular outflow in NGC 3079 offset by 14 pc with velocities -350 to -450 km/s, mass outflow rate 8.82 M_sun/yr, kinetic power 3.8e41 erg/s, and momentum rate 15 times the AGN radiation momentum, indicating an energy-driven jet-powered outflow.
New ALMA [C II] and FIR data on PSO J083+11 at z=6.34 reveal ordered rotation, typical star-forming ratios, and no outflow signatures in either galaxy, interpreted as a pre-AGN-feedback accretion phase.
Calibrated AGN disk-wind models contribute ≲5% to the CGB above 10 GeV and ≲10% to the CNB at 100 TeV and are unlikely to dominate either background.
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.
Panchromatic SED modeling yields SFRs with smaller offset and scatter than optical-only fits for starburst to post-starburst galaxies, while Prospector AGN torus models distinguish AGN but underpredict luminosities by an order of magnitude.
New ALMA observations of NGC 5506 show a thick rotating CND where supernova-driven turbulence supplies vertical support and AGN outflow dissociates CO.
Energy extraction via Comisso-Asenjo magnetic reconnection from rotating dyonic black holes in N=2 U(1)^2 gauged supergravity is possible but tightly limited by gauge coupling g and dyonic charges, peaking at intermediate spins rather than near-extremal.
A workshop report recommends anomaly detection on existing telescope data to search for technosignatures from advanced minds powered by supermassive black holes.
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Changing-Look AGN Powered By Disk Tearing
High-resolution GRMHD simulations show that tearing of tilted accretion disks around rapidly spinning supermassive black holes drives order-of-magnitude variability in continuum and broad-line luminosities on months-to-years timescales, explaining changing-look AGN.