Weekly archive
LRDigestWeekly digests of little red dots and JWST-selected AGN papers, with curated reading notes and archive pages.
654 indexed papers · 430 research notes
Using JWST mid-infrared IFS of NGC 5728, the authors decompose blended circumnuclear line emission into a star-forming ring and AGN bicone. Stacking twelve tracers yields spatial flux fractions that are stable across tested weighting choices.
Radiative-transfer calculations suggest that slow, off-axis fountain winds from super-Eddington engines can reproduce LRD-like Balmer breaks and P-Cygni-plus-scattering line profiles, while attributing broad wings to electron scattering rather than virial motions.
A single z=7.03 galaxy–absorber pair links a dusty, intensely star-forming galaxy to unusually strong multiphase metal absorption at 16 kpc. Blueshifted gas is consistent with an outflow, while abundance evidence for Population III enrichment remains suggestive rather than decisive.
For 142 optically unobscured, FIR-bright Stripe 82 quasars at z=1–4, ALMA deblending lowers inferred host SFRs yet leaves extreme starbursts. The authors find weak instantaneous starburst–accretion coupling and UV-line differences consistent with a transitional interpretation.
Ultra-deep JWST/SPURS rest-UV spectra of four UV-bright Little Red Dots find dense, nitrogen-enhanced, neutral-gas-embedded nuclei and diverse broad-line/wind signatures. The authors infer compact nuclear activity, while stellar and AGN contributions remain degenerate.
RUBIES-EGS-9809 is a single, heavily obscured broad-line AGN host at z=5.7 whose resolved Balmer break and declining-SFR SED fit make it a quenching candidate, not a confirmed post-starburst. Outflow signatures make AGN feedback plausible but unproven.
Using infrared SED fits to two low-redshift LRD analogs and an assumption-driven population model, the authors argue that LRD outflows could add appreciably to high-redshift dust production, but neither dust origin nor cosmic importance is established.
Spatially resolved JWST/MIRI spectroscopy of five nearby AGN links contrasting PAH-ratio trends to AGN irradiation and shock-processing diagnostics. The authors interpret their coexistence as a route to nuclear PAH suppression and to divergent PAH star-formation calibrations.
Among 40 JWST-selected LRDs, 14 show Hα absorption, far exceeding SDSS type-1 AGNs; the compiled absorbers are mostly blueshifted and kinematically narrower, consistent with line-of-sight outflows but not uniquely establishing their fate.
This review argues that SKA radio morphology, spectra and polarimetry, tied to redshift-resolved environmental maps, can turn radio galaxies into statistical cosmic-web probes; its quantitative examples are forecasts and pathfinder benchmarks rather than new SKA measurements.
XRISM/Resolve spectroscopy of the z=0.297 quasar cluster H1821+643 measures unusually broad ICM Fe XXV lines, implying substantial non-thermal motions on 20–100 kpc scales. The authors interpret these motions as quasar-feedback coupling, but resonance scattering and sloshing remain relevant alternatives.
JADES-GS 209777 (“the Hatchling”) is a z=3.711 red quasar with exposed broad-line/X-ray emission yet nuclear absorption and multiphase disturbed gas. The authors interpret this combination as a partially cleared, dusty buried-quasar phase.
In one extreme z~6 halo, simulations predict that earlier seeding plus mildly super-Eddington growth drives cold, fast, neutral CGM clumps and extended Hα after feedback clears nuclear sightlines; this is a model prediction, not a population measurement.
Completeness-corrected JWST/NIRSpec fits indicate strong Hα absorption is common in little red dots (LRDs) but not detected in little blue dots, favoring blueshifted, likely outflowing gas while leaving rest-frame absorption substantially incomplete.
The authors argue that supercritical accretion can launch an optically thick LRD outflow whose red photosphere, line broadening, and Balmer-break properties are broadly compatible with observations, while its Balmer decrements remain underpredicted.
Using X-ray spectra of the single nearby, long-quenched galaxy KUG 1208+386, the authors report a ≈0.07c nuclear ultra-fast outflow. Its ≥3σ trial-corrected line evidence makes feedback in a quiescent host plausible, but not yet a demonstrated maintenance mechanism.
This is a proposed ELT/VESPER integral-field program, not a feedback detection: it will map eleven z=1.5–2.5 obscured, starbursting radio AGN to test whether spatially resolved jet–ISM associations coincide with shocks, outflows, and altered star formation.
The authors propose that Little Red Dots are dense-wind, super-Eddington engines analogous to Type IIn supernova interaction phases, rather than virial broad-line AGN. Their escape-velocity interpretation gives a typical-engine upper limit below 10^5 solar masses.
JWST/MIRI PCA tomography recovers 11.3-μm PAH velocity maps in three of five z~0.1 type-2 quasars; all three show dust-traced outflow kinematics, with molecular-gas residuals consistent with outflow after disk subtraction.
For the single z=5.482 Little Red Dot LRD-204851, aligned UV, optical-line, and Lyα structures indicate a narrow bipolar channel extending several kpc. Lyα transfer fitting favors slow expansion, but cannot distinguish an outflow from a quasi-static ionization cone.
KOOLS-IFU maps of NGC 6552 find broad [O III] emission declining with radius but no significant full-sample association between local kinematics and [O III]/Hβ excitation, favoring spatial dynamical structure over a detected excitation–kinematics coupling.
Across six JWST/NIRSpec IFU targets at z=3–9, resolved stellar-population histories associate strong AGN-driven ionized outflows with recent nuclear quenching in the most massive systems, while starburst-driven outflows accompany continued growth in lower-mass galaxies.
Spatially resolved JWST, ALMA and KCWI data support a multiphase, minor-axis biconical outflow in the dusty local merger IRAS F01364-1042. The authors infer faster ionized than molecular gas and argue a nuclear starburst can energetically drive it despite an obscured AGN.
High-resolution JWST/NIRSpec spectra of 10 compact, color-selected LRDs at 3<z<7 recover Balmer absorption in four. The authors argue resolution exposes frequent, diverse excited-hydrogen absorption, but the small, selected sample limits population-level inferences.
A DESI DR1 selection identifies 27 candidate low-redshift LRDs at z=0.2–0.9; near-IR spectra of 18 show broad, highly decremented Balmer lines and unusual continua, supporting—but not independently proving—continuity with high-redshift LRD phenomenology.
JWST/MIRI-MRS resolves a warm-H₂ outflow in the composite ULIRG F10565+2448: it is hotter than the disk but apparently sub-escape-speed, while a faster unresolved ionized component and localized shock candidates support multiphase feedback.
JWST/MIRI-MRS mapping of seven nearby radio-loud AGN links elevated warm-H2 excitation and broadened multiphase gas to radio-jet environments, including transverse regions. The authors interpret the correlations as predominantly jet-driven shocks, while recognizing source-dependent exceptions.
JWST IFU spectroscopy of NGC 7582 separates rotating circumnuclear-disk gas from an AGN bicone by ionisation potential and line-profile decomposition, finding distinct kinematic axes and broader outflow lines; mixed-ionisation tracers require two components.
Medium-resolution JWST/NIRSpec data spatially separate an LRD-like AGN and its host at z=6.64, revealing exceptionally broad ionised gas consistent with AGN driving but a low inferred mass-loading factor and therefore limited immediate star-formation impact.
PAN-BH*-1 is a single z=1.731 Little Red Dot at cosmic noon with an extreme Balmer break, compact red continuum, and broad Hα absorption. Its data are consistent with—but do not establish—a thick, rotating photospheric disk wind.
XRISM Resolve spectroscopy of the crowded Galactic-centre field isolates narrow iron-line emission attributed to the black-hole candidate MAXI J1744-294, including static highly ionized gas and atypical features consistent with blueshifted material, though plasma origin and background systematics remain unresolved.
Across SDSS quasars at 0.2<z<2.4, compact red quasars show an excess near α1.4–3 GHz≈−1 that strengthens with dust extinction. The authors interpret this as wind/jet–ISM shocks during a dusty blow-out phase, but radio spectra alone do not establish that mechanism.
In 18 z≈3–7 broad-Hα emitters, Balmer cores progress from narrow emission to P-Cygni-like and absorption-dominated profiles as UV–optical colour reddens. The authors interpret this as changing envelope column density and optical depth, not purely dynamical line broadening.
JWST IFU observations of 10 local Seyferts use PCA tomography of broad PAH bands to map dust-phase kinematics. The authors report neutral, larger PAHs sharing molecular and ionised-outflow signatures in NGC 5728 and NGC 7582, while 3.3 μm PAHs trace disks.
Among 10 UV-selected, extremely luminous radio-quiet non-BAL quasars with confirmed C IV outflows, only two are X-ray weak. A possible X-ray-weakness/outflow link appears only above 3000 km s⁻¹ and is tentative (~2σ).
Long-slit spectroscopy of Stephan’s Quintet separates NGC 7319’s rotating disk, ionized AGN outflow, and tidal bridge: the authors infer a ≤550 km s⁻¹ outflow peaking at 2.6 kpc, with tidal motions increasingly dominant beyond 2.4–6.3 kpc.
Five-epoch spectroscopy of three AGNs with A_V>50 mag finds broad-Hα behavior is not uniform: Mrk 268 varies at 4.3σ, consistent with direct BLR emission, whereas MCG -3-34-64 and UGC 5101 favor outflow and/or scattering contributions.
JWST 3–28 μm nuclear spectroscopy of four low-luminosity AGN associates weak high-ionization emission, shock-like line ratios, altered PAH populations, and non-thermal H₂ excitation with feedback, while leaving the proposed jet connection indirect.
JWST/NIRSpec IFU data identify ionized-outflow signatures in 14 of 40 regions of massive, non-AGN star-forming systems at z≈3–9. The authors infer dusty, metal-enriched but gravitationally retained gas, implying redistribution rather than efficient ejective feedback.
JWST/MIRI imaging of eight nearby Seyferts finds resolved 100–200 pc NLR dust in four. Its warm, steep mid-IR SEDs exceed simple AGN-heating predictions; the authors therefore favor local shock heating, while treating shocks as an interpretation rather than a direct calorimetric detection.
![Figure 1 from Shedding the envelope: JWST reveals a kiloparsec-scale [OIII]-weak Balmer shell around a z=7.64 quasar](/lrdigest/research/figures/2512.15881v1/figure-1-1.png?v=9c4c172c8f786a6a)
JWST/NIRSpec IFU data reveal Hβ emission to ~1.8 kpc around the z=7.64 quasar J0313−1806 but no significant [O III]. The authors favor dense, clumpy fossil-outflow gas, while the single-object data leave its geometry and evolutionary interpretation uncertain.
Cosmological simulations of a 5×10^7 M⊙ primordial-black-hole seed reproduce several inferred properties of Abell 2744–QSO1 at z≈7, but establish a viable model pathway rather than evidence that its black hole is primordial.
JWST/MIRI plus MUSE resolves a dusty, multiphase ionized outflow in NGC 1068: [O IV] is 300 km s⁻¹ faster than [O III], and the authors infer that optical data miss much of the ionized outflow mass.
JWST/NIRSpec IFU maps of four dwarf AGN with [O III] outflows find extended, predominantly AGN-photoionized near-IR coronal emission and compact broad components. The results link coronal-line visibility to outflows, but small-sample correlations do not establish causation.
New Chandra coverage makes the X-ray census nearly complete for the brightest known z~7 quasars, finding broadly familiar UV–X-ray scaling but substantial scatter, a tentative wind–SED association, and a soft stacked X-ray spectrum consistent with high accretion rates.
Two z~3 X-ray AGNs with He I λ10830 absorption indicate dense, broad-line-region-scale circumnuclear gas, but their contrasting obscuration, accretion rates, and outflow signatures provide only a two-object, model-dependent case for an evolutionary sequence.
Forward modeling of JWST/MIRI-MRS spectra for 25 AGN favors heterogeneous radial dust distributions: 14 sources prefer n(r)∝r⁻⁰·⁵ and 8 prefer r⁻². Assumed density structure can shift inferred AGN fractions by up to fourfold.
This abstract-only paper proposes that little red dots are nascent AGN systems containing sub-million-solar-mass central black holes plus a more massive embedded stellar-mass-black-hole population, attributing their V-shaped SEDs and Balmer absorption to distinct, model-dependent components.
JWST/NIRSpec IFU observations of 27 luminous z≈5–6 quasars find ≈10^9 M⊙ actively accreting black holes and extended [O III] in six systems; nuclear optical properties broadly resemble lower-redshift quasars, while shallow data limit environmental inferences.
A 280 ks Chandra study identifies the z=3.631 Hot DOG W0410-09 as a Compton-thick, intrinsically luminous quasar and finds tentative stacked Fe Kα evidence for obscured AGN among nearby Lyα emitters, but not individual LAE detections.
BALNet uses simulated SDSS DR16Q spectra to segment C IV BAL troughs and infer velocities. On DR16Q at 1.5≤z≤5.7, it identifies BALs in 20.4% of spectra, but simulated-test performance and weak/narrow-feature losses limit catalog interpretation.
A joint luminosity-function and escape-fraction model attributes 31–75% of z>5 ionizing photons to AGN, but the result depends on assumed galaxy escape fractions and an outflow-based AGN LyC-escape prescription available here only in the abstract.
In twelve z=6.0–6.4 low-luminosity SHELLQs quasars, wavelength-dependent PSF subtraction isolates extended host emission. The authors report mostly main-sequence-consistent Hα upper-limit SFRs, one [O III] outflow, and one disk-like rotation, while narrow-line-region contamination complicates interpretation.
A 27-object z~6 SHELLQs sample is interpreted as very young, ionizing starbursts; JWST/ALMA observations of J0217-0208 link its exceptional UV brightness to compact star formation and a dusty ionized outflow, though the proposed causal link remains model-dependent.
Gemini/GMOS IFU plus archival SED data identify J2048 at z=0.4330 as an LRD-like AGN with spatially extended young-starburst and ionized-outflow signatures; the authors infer a ~400 M⊙ yr⁻¹ SFR and an unusually high inferred black-hole-to-stellar-mass ratio.
JWST/MIRI mapping of 54 nearby galaxies finds broader ionized than warm-H2 lines in AGN, especially radio-strong systems; line-ratio/model comparisons associate the most turbulent gas with shocks, while the authors cautiously propose AGN or stellar-feedback origins.
![Figure 7 from The warm outer layer of a Little Red Dot as the source of [Fe II] and collisional Balmer lines with scattering wings](/lrdigest/research/figures/2510.00103v1/figure-7-1.png?v=68cb82fd0486ea51)
Deep JWST spectra of the single z=5.535 LRD GN-9771 reveal optical [Fe II] and unusual Balmer profiles consistent with a dense, ∼7000 K radiative-transfer layer; if scattering dominates the wings, standard virial black-hole masses may be biased high.
JWST spectroscopy of M58’s central kiloparsec resolves warm H₂ in dust lanes and a turbulent inner region; the authors infer predominantly low-velocity C-type shocks, with lower-density non-thermal excitation affecting rovibrational lines near the LLAGN.
XRISM/Resolve’s 2024-02-25 spectrum of the neutron-star binary GX 13+1 reveals a stratified, highly ionised, Compton-thick wind via dozens of narrow, slightly blueshifted lines from Si–Ni, including high-order Fe XXV/XXVI features above 7 keV. Photoionisation fits require a slow, very dense absorber plus a faster (~700 km/s), more ionised layer to reproduce the Fe XXVI Ly blue wing and residual core flux from wind reprocessing. After correcting for electron-scattering attenuation, the intrinsic luminosity is at or above Eddington, yet the outflow is extremely slow, favouring a thermal‑radiative outer-disc origin over an inner-disc radiation‑pressure (Eddington) wind. The contrast with ultrafast (~0.3c) SMBH winds at similar Eddington ratios points to fundamentally different launch mechanisms across mass scales.
A radiation–GRMHD suite with angle-discretized transport follows super‑Eddington inflow across accretion rates, spins a*≈0.3–0.94, and single/double‑loop fields, finding robust, radiation‑pressure supported thick disks. Inner‑disk radiation drives powerful outflows that carve conical funnels, trap photons, and keep radiative efficiencies low while thermal transport is dominated by advection. Angular momentum is carried mainly by Maxwell stress; jets occur in weak and strong modes, with strong jets (net vertical flux + high spin) evacuating the funnel and enabling geometrically beamed escape, whereas weak jets leave the funnel clogged and dimmer—implications for ULXs and little red dots. Spiral density waves appear in the plunging region, adding structure to the inner flow.