A hierarchical Bayesian framework that uses the empirical anti-correlation between AGN variability amplitude and luminosity to infer cosmological parameters from moderate-baseline light curves via importance reweighting.
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The Low-Luminosity End of the Radius-Luminosity Relationship for Active Galactic Nuclei
26 Pith papers cite this work, alongside 773 external citations. Polarity classification is still indexing.
26
Pith papers citing it
773
external citations · Pith
abstract
We present an updated and revised analysis of the relationship between the Hbeta broad-line region (BLR) radius and the luminosity of the active galactic nucleus (AGN). Specifically, we have carried out two-dimensional surface brightness decompositions of the host galaxies of 9 new AGNs imaged with the Hubble Space Telescope Wide Field Camera 3. The surface brightness decompositions allow us to create "AGN-free" images of the galaxies, from which we measure the starlight contribution to the optical luminosity measured through the ground-based spectroscopic aperture. We also incorporate 20 new reverberation-mapping measurements of the Hbeta time lag, which is assumed to yield the average Hbeta BLR radius. The final sample includes 41 AGNs covering four orders of magnitude in luminosity. The additions and updates incorporated here primarily affect the low-luminosity end of the R-L relationship. The best fit to the relationship using a Bayesian analysis finds a slope of alpha = 0.533 (+0.035/-0.033), consistent with previous work and with simple photoionization arguments. Only two AGNs appear to be outliers from the relationship, but both of them have monitoring light curves that raise doubt regarding the accuracy of their reported time lags. The scatter around the relationship is found to be 0.19(+/-0.02) dex, but would be decreased to 0.13 dex by the removal of these two suspect measurements. A large fraction of the remaining scatter in the relationship is likely due to the inaccurate distances to the AGN host galaxies. Our results help support the possibility that the R-L relationship could potentially be used to turn the BLRs of AGNs into standardizable candles. This would allow the cosmological expansion of the Universe to be probed by a separate population of objects, and over a larger range of redshifts.
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representative citing papers
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.
Blind tests on simulated disc-wind BLR data show standard RM methods recover rotation but miss wind geometry and yield inconsistent velocity-delay maps despite good spectral fits.
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.
Using simultaneous modeling of continuum lag-spectrum and broadband SED of Fairall 9 with the H0RIZON-AGN model, the authors obtain H0 = 72.4_{-3.7}^{+3.4} km s^{-1} Mpc^{-1}.
LRDs are interpreted as high-inclination hyper-Eddington accreting SMBHs analogous to SS 433, with V-shaped SEDs, X-ray weakness, and Balmer breaks emerging from disk self-shielding geometry.
LRDs at z~3-7 exhibit an L_Hα,broad-L_bol scaling relation enhanced by a factor of ~40 compared to low-z Type 1 AGN, explained via Cloudy modeling with near-unity covering factor and high column density.
DESI DR1 yields 314k high-mass and 9.6k dwarf AGN, extending the M_BH-M_star relation to log M_star ~7.8 and suggesting two evolutionary pathways for galaxies and black holes.
Slim-disk self-shadowing plus accretion-rate-dependent BLR density enhancement explains the observed offsets of high-Eddington AGNs below the canonical R-L relation.
A theoretical model of a magnetized black hole envelope is developed to explain the broad emission lines and X-ray faintness observed in little red dots using co-rotating plasma clumps and limited X-ray sources.
Optical-MIR lags of 39.1 days and 79.4 days are measured in Mrk 42 and Mrk 493, yielding dust reverberation radii of 0.032 pc and 0.065 pc with R_dust/R_BLR ratios of approximately 6-7.
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.
Elliptical BLR geometries cause the virial factor f to vary by over an order of magnitude and induce ~0.18 dex scatter in the R-L relation, challenging attributions of RM uncertainties to non-virial motions or radiation pressure.
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.
Presents a public spectroscopic atlas of 887 Southern broad-line AGNs at low redshift, including continuum decompositions and emission-line fits.
Efficient neutrino production requires an external radiation field stronger than the magnetic field near the broad-line region, but this conflicts with single-zone broadband emission, implying the neutrino site must be physically separated from the dominant electromagnetic zone in uncommon jet confi
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%.
Mid-infrared lines near Sgr A* exhibit no detectable variability during flares, because light-crossing and recombination timescales in the extended gas suppress responses, so the lines cannot constrain instantaneous UV flux.
HE 1237-2252 exhibits a changing-look event driven by intrinsic accretion-rate variations, revealing a two-component broad-line region consisting of virialized gas at ~27 light-days and disk emission at larger radii.
2MASX J0413-0050 transitioned from a narrow-line Seyfert 1 to a Seyfert 1.9 and back while remaining in a high accretion state, supporting classification as a changing-state AGN.
A statistically significant positive correlation (r ~ 0.12-0.13) exists between the absolute velocity offset of broad Hβ lines and dust reddening in quasars, consistent with a population of recoiling black holes.
Multi-epoch spectroscopy of UNAM-KIAS 613 shows transient double-peaked broad Hα emission interpreted as a one-time bipolar outflow in an isolated low-luminosity AGN with Eddington ratio ~0.03-0.04.
Simultaneous observations of NGC 4151 and UGC 3374 show that ICCF-Cut photometric Hα light curves and lags match spectroscopic results within uncertainties, with minor discrepancies attributed to He I contamination that can be corrected.
Reverberation lags in Mrk 817 range 3-8 days, exceed thin-disk models by factors of 3-6, follow a λ^{4/3} trend with the ICCF method, and vary by up to a factor of 2 between epochs.
citing papers explorer
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Little Red Dots as Supermassive Analogs of SS 433
LRDs are interpreted as high-inclination hyper-Eddington accreting SMBHs analogous to SS 433, with V-shaped SEDs, X-ray weakness, and Balmer breaks emerging from disk self-shielding geometry.
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Radiation-pressure instability is an artifact of constant-$\alpha$ closure
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.
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Locating the Production Sites of High-Energy Neutrinos in Blazar Jets
Efficient neutrino production requires an external radiation field stronger than the magnetic field near the broad-line region, but this conflicts with single-zone broadband emission, implying the neutrino site must be physically separated from the dominant electromagnetic zone in uncommon jet confi
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Population synthesis of active galactic nuclei based on the radiation-regulated unification model
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%.
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Infrared Line Diagnostics Fail to Constrain Sgr A*'s UV Output
Mid-infrared lines near Sgr A* exhibit no detectable variability during flares, because light-crossing and recombination timescales in the extended gas suppress responses, so the lines cannot constrain instantaneous UV flux.
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An X-ray and optical spectral study of the changing-look narrow-line Seyfert 1 2MASX J0413-0050
2MASX J0413-0050 transitioned from a narrow-line Seyfert 1 to a Seyfert 1.9 and back while remaining in a high accretion state, supporting classification as a changing-state AGN.
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Estimation of black hole spins in low-mass AGNs and comparison with other types of AGNs
Spins of low-mass AGN black holes decrease with mass, supporting mergers or chaotic accretion as growth mechanisms and suggesting an evolutionary sequence where spins first decrease then slowly increase.