Detection of a variable stratified UFO with velocities 0.1c and 0.3c, extreme mass outflow rates, and kinetic powers of 1-10% of bolometric luminosity in quasar WISSH13 at z=3.294.
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Unified Schemes for Radio-Loud Active Galactic Nuclei
Mixed citation behavior. Most common role is background (60%).
62
Pith papers citing it
4,269
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Background
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abstract
The appearance of active galactic nuclei (AGN) depends so strongly on orientation that our current classification schemes are dominated by random pointing directions instead of more interesting physical properties. Light from the centers of many AGN is obscured by optically thick circumnuclear matter and in radio-loud AGN, bipolar jets emanating from the nucleus emit light that is relativistically beamed along the jet axes. Understanding the origin and magnitude of radiation anisotropies in AGN allows us to unify different classes of AGN; that is, to identify each single, underlying AGN type that gives rise to different classes through different orientations. This review describes the unification of radio-loud AGN, which include radio galaxies, quasars, and blazars. We describe the classification and properties of AGN and summarize the evidence for anisotropic emission. We outline the two most plausible unified schemes for radio-loud AGN, one linking quasars and luminous radio galaxies and another linking BL~Lac objects and less luminous radio galaxies. Using the formalism appropriate to samples biased by relativistic beaming, we show the population statistics for two schemes are in accordance with available data. We analyze the possible connections between low- and high-luminosity radio-loud AGN. We review potential difficulties with unification and conclude that none currently constitutes a serious problem. We discuss likely complications to unified schemes that are suggested by realistic physical considerations; these will be important to consider when more comprehensive data for larger complete samples become available. We conclude with a list of the ten questions we believe are the most pressing in this field.
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representative citing papers
Magnetized disk models lower the thermal-viscous instability threshold to Eddington ratios of 0.01-0.03 and yield limit-cycle timescales of months to years, jointly matching observations in five CLAGN only when the inner disk is strongly magnetized.
An analytical derivation of maximum neutrino flux in the one-zone leptohadronic model shows predicted fluxes remain below IceCube levels for neutrino-candidate blazars.
Red quasars are intrinsically X-ray weak with low alpha_OX values, tracing a distinct evolutionary stage of suppressed black hole accretion relative to stellar mass growth.
A causal machine-learning model using variability features from Fermi-LAT light curves predicts blazar flare activity within 90 days with 86% recall on held-out data for one FSRQ.
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.
Confirmation of 77 new heavily reddened quasars at 1.5 < z < 3.9 with high luminosities and extinctions, showing they are deficient in hot and warm dust relative to blue quasars and supporting a blow-out feedback phase.
Multimessenger observations and one-zone leptohadronic modeling of PKS 1725+123 during a flare constrain its emission to external Compton gamma-rays, SSC X-rays, and a neutrino rate of about 0.3 events per year peaking at 1 PeV.
J1105+1452 transitioned to a megahertz peaked-spectrum source with a new compact jet of radius ~0.68 pc, apparent velocity ~0.64c, and Doppler factor ~12, while X-ray emission stayed disk-corona dominated.
A changing-look AGN exhibits a rapid accretion-driven spectral transition with broad-line region temperatures of approximately 11,800 K measured via Boltzmann plots and stable black hole mass estimates of 5 times 10 to the 7 solar masses across epochs.
A lens model from Gaia DR3 and HST data combined with a Bayesian test on Chandra observations constrains the X-ray emission origin in lensed quasar J0659 to a 0.020 × 0.010 arcsec ellipse offset 0.014 arcsec from the optical source at 1σ.
Tentative double Gaussian excess at 1.59 GeV (2.6σ) and 11.15 GeV (3.7σ) in Fermi-LAT spectrum of blazar 4FGL J0604.9-0000, combined TS ≃ 27 (~4.3σ local).
This paper derives quantitative correction factors for traditional SSA minimum energy estimates to account for inhomogeneity and non-spherical geometry in emitting regions.
Low-luminosity AGN exhibit structure function slopes rising from 0.1 to 0.3 with black hole mass, no breaks on decadal scales, amplitude anticorrelated with luminosity and positively correlated with mass.
Detection of a persistent ~433-day optical QPO in blazar 3C 454.3 at 2.53σ significance using Lomb-Scargle, WWZ, and PDM methods, with a new test for seasonal gaps.
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.
A criterion of |Δg| > 0.4 mag and |Δ(g-r)| > 0.2 mag detects photometric CL-AGN transitions in 9.6% of known hosts with 1.6% false positive rate from simulations.
SPENDER autoencoder plus k-d tree nearest-neighbor classification on DESI spectra identifies AGN and broad-line AGN at accuracies 0.952 and 0.965, recovering sources missed by single-line diagnostics.
A leptonic jet model with stochastic turbulent acceleration predicts hard and soft X-ray Fourier lags plus a transition regime in HBLs, with STA and nonlinear SSC cooling amplifying lags and explaining trends with flare duration.
JWST prism spectroscopy of 200 massive galaxies at z~3-15 shows normal star-forming galaxies dominate at z>6 while dusty systems and quiescent galaxies increase at lower redshift, with evidence for multiple quenching pathways.
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.
Presents a public spectroscopic atlas of 887 Southern broad-line AGNs at low redshift, including continuum decompositions and emission-line fits.
Biconical disk-wind models show that small acceleration length R_v plus high terminal velocity is required to produce detached blueshifted CIV absorption in synthetic spectra at intermediate inclinations.
Seyfert 2 galaxies show detectable optical variability, enabling estimates of scattering region sizes consistent with the obscuring torus via amplitude matching to Seyfert 1s.
citing papers explorer
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HI 21-cm absorption in low- and high-excitation radio-loud AGNs at $z<0.5$ from MALS
Five new HI 21-cm absorption detections in LERGs and HERGs at z<0.5 reveal disturbed gas kinematics with velocity offsets over 350 km/s and a 3% detection rate consistent with lower-redshift samples.
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Constraining Orbital Eccentricity of a Supermassive Black Hole Binary Candidate PKS 2131-0211
Bayesian fitting of an eccentric Keplerian orbit to the radio light curve of PKS 2131-021 gives e = 0.053 ± 0.015 without red noise but favors a circular orbit plus DRW noise with e < 0.15.