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.
A disk-plus-dichroic-transmission model can reproduce the ∼1.5% optical continuum and ∼0.7% broad-Hα polarization of the local LRD analog J1025+1402, but the spectropolarimetry constrains continuum polarization more directly than accretion rate or inclination.
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.
Multi-wavelength follow-up overturns J0109−5424’s proposed high-redshift lens interpretation: Paschen lines place it at z=2.07 as a FeLoBAL quasar. For P170+20, compact imaging and a quasar+M-dwarf spectral fit disfavor, but do not exclude, lensing.
In SDSS-IV/eBOSS, [Ne V] produces a large, high-purity but incomplete AGN sample: detection favors less-obscured, higher-Eddington-ratio nuclei. Stacking indicates many individual non-detections are sensitivity-limited, while [Ne V]/[O III] declines with AGN luminosity.
JWST multi-epoch imaging identifies PLATE-23a at z=0.688 as a strongly favored Type IIP supernova candidate, with cooling early-time SEDs and late evolution resembling local Type IIP events, while sparse late photometry limits physical inferences.
J2048, a z=0.4332 local little-red-dot analog, is detected at 3 GHz with radio luminosity 1.2×10^41 erg s^-1 and a relatively flat synchrotron-like spectrum, making it far brighter than the previously detected local analog J1047+0739.
In 20 LRDs, extreme broad Balmer decrements require both dense, optically thick non-Case-B line formation and—when Hα/Hβ exceeds the model ceiling—additional broad-line-region-associated dust, rather than galaxy-wide extinction alone.
In an SDSS broad-line sample at z<0.35, the authors identify nine SED-selected local LRD analogues and infer an abundance of 0.08%, supporting rarity at late times but with important spectral-coverage and contamination caveats.
VLT/FORS2 spectropolarimetry of the z≈0.1 LRD J1025 finds an intrinsically polarised, nearly grey continuum and a weaker, differently angled broad Hα component. The 48±4° angle offset robustly requires broken axial symmetry, but does not identify its physical cause.
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.
XMM J130514.64-493311.27 is a soft, recurrent off-nuclear X-ray transient in NGC 4945. Its 2022 XMM-Newton luminosity of about 2.3×10^38 erg s^-1 and disk-like spectrum favor an X-ray binary, while the compact object remains unresolved.
Chandra and Keck/DEIMOS observations identify two obscured, broad-line AGN in the interacting Green Pea system J1622+3521, separated by 8.4 kpc. The authors therefore report a confirmed dual AGN in a compact low-mass Green Pea environment.
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.
JWST/MIRI resolves dusty point sources across Centaurus A’s warped disc: 928 red infrared-excess objects are consistent with embedded young stellar objects and follow the disc rather than the radio jet, favoring merger-accreted gas as the immediate star-formation reservoir.
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.
OzSSy1 releases uniform WiFeS spectroscopy, decompositions, and line measurements for 887 southern broad-line AGNs at z<0.1, providing a local reference sample while retaining incompleteness from host dilution at the lowest redshifts.
SDSS color selection identifies ~1,300 low-redshift “LoRD” quasars whose V-shaped subset resembles LRD spectral energy distributions, but host contamination, unresolved morphology, and weak high-z X-ray limits prevent establishing them as a uniformly faithful analog population.
Swift eclipse monitoring of ESO 362-G18 uses time-resolved absorption changes to constrain an X-ray source within ~35 Rg. The authors infer a structured cloud and a soft-excess region ~50% larger than, yet overlapping, the hot corona.
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.
In 18,749 DESI-DR1 NLSy1s, stronger Fe II and lower single-epoch virial masses than SDSS-DR17 correspond to a larger inferred super-Eddington fraction. Two mass calibrations preserve the population difference, but virial-mass systematics remain consequential.
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.
Among 14,584 SDSS type-1 AGNs at z<0.35, seven robust Balmer absorbers imply a ∼0.05% incidence. Joint, resolution-aware Balmer fitting finds narrow, generally saturated absorbers; a rare high-Eddington, weak-Fe II subset may be preferentially affected.
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.
Using simulation-based inference on a synthetic local AGN population, the authors find an intrinsic Compton-thick fraction of 40±3%. Their radiation-regulated geometry broadly reproduces several X-ray observables, but depends materially on fixed, simplified broad-line-region and torus assumptions.
A DESI DR1 line-selected search identifies eight compact z=0.20–0.44 LRD candidates with broad, steep-decrement Balmer emission, low-excitation spectra, and generally weak multi-year variability, extending detailed LRD tests to the nearby Universe.
eROSITA-triggered monitoring of HE 1237-2252/J1240−2309 links a changing-look transition to intrinsic accretion-rate recovery and an evolving two-component Balmer-line profile. A diskline-like component strengthens with UV flux, while the proposed corona/illumination mechanism remains interpretive.
Across four optical and three X-ray epochs, J0413-0050 changed from broad Balmer emission in 2004 to an Hβ-free 2021 state and back to broad plus narrow Hβ in 2023. The authors favor changing accretion over obscuration, but X-ray column density is unconstrained.
Local AGN-hosting dwarfs can mimic Little Red Dot-like V-shaped continua, but their systematically larger sizes and predominantly low-redshift-like ionization indicate they are unlikely to be direct local counterparts of high-redshift LRDs.
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.
For the single $M_\star\sim10^{10}\,M_\odot$ host GAMA 376183, NuSTAR and multiwavelength data support a heavily obscured, rapidly accreting AGN in a disturbed system; the proposed merger-triggered starburst/accretion connection remains suggestive rather than demonstrated.
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.
Five DESI DR1 sources at z=0.2–0.4 reproduce LRD-like V-shaped SEDs and broad Balmer lines, but their AGN-like line ratios and substantially larger hosts make an evolutionary connection to z>4 LRDs plausible rather than established.
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.
In a 140 deg² eROSITA field, the authors identify eight z=0.3–0.8/1 quasars with inferred M•/M⋆>5%. Their abundance supports recurrent black-hole/host offsets among rapidly accreting AGN, but single-epoch masses and often upper-limited host masses temper the conclusion.
Two z≈0.7 compact dwarfs combine blue, burst-dominated UV–optical emission with a MIRI hot-dust excess. SED-inferred AGN luminosities imply candidate black holes disproportionately massive for ≈10^7 M⊙ hosts, but masses depend strongly on the assumed Eddington ratio.
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.
Six-year ZTF monitoring of seven z~0.3 LRD analogs detects multiband excess variance in three and DRW-like variability in two, supporting—but not establishing—an AGN interpretation. Simulations suggest present JWST high-z variability upper limits can be biased low by short baselines.
Semi-supervised adaptation from DESI-derived mocks to J-PAS observations improves held-out four-class photometric classification over mocks-only and equally label-limited J-PAS-only baselines, chiefly for quasars. Results demonstrate mitigation of this specific simulation-to-observation shift, not a general guarantee of transferability.
For 194 X-ray AGN at z<1.5 in GOODS, the authors find predominantly obscured SEDs and mainly disk-dominated hosts. A statistically distinct, faint obscured SED class is more spheroid-rich, while the observed interaction fraction does not establish triggering causality.
For 63 heavily reddened quasars at z=0.7–2.7, two-component UV–IR fits frequently yield V-shaped SEDs and comparatively weak hot dust. The authors identify four cosmic-noon objects meeting Little Red Dot continuum-slope selections, but do not uniquely establish the UV-emission mechanism.
JWST NIRSpec/MIRI nuclear spectra of eight LLAGN plus Cen A associate decreasing [Ne V]-to-X-ray output below log(Lbol/LEdd)≈−3.5 with a UV-deficient ionizing SED, while finding warmer rotational H2 and predominantly nuclear silicate emission.
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.
In local merging (U)LIRGs, 230-GHz continuum combined with X-ray luminosity and IR-based SFR can conservatively separate star-formation-compatible systems from candidate obscured AGN; the authors identify one confirmed AGN and two strong candidates, but calibration remains preliminary.
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/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.
JWST/CEERS SED fitting identifies 1,361 candidate low-mass galaxies with unexpectedly high attenuation. Their similar sizes and axis ratios to non-dusty dwarfs disfavor a simple edge-on explanation, while modest clustering and lower inferred sSFR motivate—but do not establish—environmental evolution.
ALMA CH–H2O absorption toward two lensed quasars finds no significant differential velocity and, with independent μ bounds, limits |Δα/α| to 0.55 ppm at zabs=0.88582, a sub-ppm cosmological constraint.
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.
Archival VLA data detect compact, variable synchrotron radio emission from the local LRD candidate J1047+0739. The authors favor a luminous-supernova interpretation, but the measurements remain compatible with accretion and internally inconsistent epoch flux reporting limits the inference.
Three nearby proposed Little Red Dot analogs show <3–4% optical-continuum variability over rest-frame five years; two also have broad-Hα changes below a few percent over roughly 15 years, challenging ordinary variable, photoionized broad-line interpretations.
Using two SDSS epochs of the z=0.228 quasar SDSS J0012-1022, the authors argue that an anomalous luminosity–optical-slope change is consistent with phase-dependent obscuration of two accreting black holes. It supports, but does not establish, a sub-parsec binary interpretation.
Multi-epoch SDSS spectroscopy of 1,116 nearby type-1 AGNs finds broad-line Hα/Hβ decreases as individual AGNs brighten. The authors argue continuum-driven BLR radiative-transfer and excitation changes, rather than variable intrinsic dust reddening, predominantly drive this variability.
Joint NuSTAR–XMM-Newton spectroscopy of the 60-source NEP hard-X-ray catalog yields an observed Compton-thick fraction of 0.13^{+0.15}_{-0.04}; correcting absorption bias raises the inferred underlying fraction to 0.32^{+0.23}_{-0.08}.
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.
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.