Weekly archive

LRDigest

Weekly digests of little red dots and JWST-selected AGN papers, with curated reading notes and archive pages.

Browse weekly issues, then open each paper page for the abstract, digest, figures, and PDFs.

Public archive browsing available without login.

654 indexed papers · 430 research notes

Research archive

Reset

2026-11-10 · 2611.12861v1

Little Red Dots from Primordial Black Holes: Non-Gaussianity and Accretion Evade $μ$-Distortion Constraints

Shyam Balaji, Bryce Cyr, Sarah R. Geller, et al.

Download highlighted PDFarXiv abstract

This paper asks whether primordial black holes can provide the massive seeds needed for the JWST little red dot population without violating COBE/FIRAS limits on CMB μ-distortions. Using MCMC fits for broad lognormal and cut-power-law primordial power-spectrum enhancements, including local non-Gaussianity, nonlinear density mapping, and post-formation accretion, the authors find viable LRD-seeding models with |fNL| of order unity and peak power A of order 10^-3 under standard Eddington-limited growth. Both positive and negative fNL branches can reproduce the inferred LRD abundance, but the negative branch is accretion-history dependent and disappears for low black-hole duty cycles (fduty ≲ 0.1). The result reopens a primordial-seed route to early SMBHs and makes future μ-distortion experiments a direct test of that scenario.

LRDQSO

2026-11-10 · 2611.10140v1 · Research note

Probing circumstellar interaction with spectroscopy of ZTF hydrogen-rich superluminous supernovae

Yang Hu, Ragnhild Lunnan, Priscila J. Pessi, et al.

Download highlighted PDFarXiv abstract

Across 304 ZTF optical spectra of 106 H-rich superluminous supernovae, Balmer-line modeling and comparisons support dense circumstellar interaction, but reveal no line morphology unique to SLSNe-IIn; blue-excess objects are typically fainter and favor faster fitted emitting shells.

broad Balmerspectroscopy
Figure 1 from On the importance of medium-resolution continuum spectroscopy for JWST's extragalactic legacy

2026-11-06 · 2611.07070v1 · Research note

On the importance of medium-resolution continuum spectroscopy for JWST's extragalactic legacy

Adam C. Carnall, Ho-Hin Leung, Struan D. Stevenson, et al.

Download highlighted PDFarXiv abstract

This planning paper argues that deep JWST/NIRSpec medium-resolution continuum spectroscopy can turn high-redshift galaxy surveys from emission-line detections into measurements of stellar populations, neutral gas, and kinematics; its empirical EXCELS-based exposure scaling motivates a 1,000-hour survey concept.

LRDspectroscopyhigh-z

2026-11-06 · 2611.07020v1 · Research note

The obscured nucleus of NGC3256 S. I. Anisotropic AGN near-IR radiation field traced by CO v=1-0 with JWST/NIRSpec

Miguel Pereira-Santaella, Eduardo González-Alfonso, Ismael García-Bernete, et al.

Download highlighted PDFarXiv abstract

JWST/NIRSpec CO v=1–0 emission across NGC 3256 S’s outflow base implies that the obscured AGN’s 4.7-μm radiation is anisotropic and likely collimated, though the inferred geometry depends on radiative-transfer assumptions.

JWST AGNspectroscopy

2026-11-06 · 2611.07006v1 · Research note

Black Hole Seeds and Little Red Dots: Connecting Formation and Growth with a JWST Multi-Cycle Treasury Program

Fabio Pacucci, Raffaella Schneider, Harley Katz, et al.

Download highlighted PDFarXiv abstract

This white paper proposes a coordinated, multi-cycle JWST program to determine whether Little Red Dots trace accreting black holes and to separate black-hole seeding signatures from later growth through uniform spectroscopy, imaging, and time-domain data.

LRDspectroscopyhigh-z

2026-11-05 · 2611.06334v1

Supermassive black holes and nuclear star clusters in galaxies: constraining formation and co-evolution with SHARP and MICADO

E. Dalla Bonta', E. Portaluri, C. Arcidiacono, et al.

Download highlighted PDFarXiv abstract

This SHARP and MICADO science case sets out a unified, parsec-scale program to measure supermassive-black-hole masses, nuclear-star-cluster kinematics and populations, nuclear structure, and gas-inflow signatures in nearby galaxy nuclei. The central aim is to distinguish in-situ cluster growth, star-cluster infall, and black-hole-driven cusp formation, while mapping the transition from low-mass nuclei where clusters can regulate gas supply and black-hole growth to massive core galaxies shaped by mergers and black-hole binaries. Its key practical result is to define the black-hole-mass and distance regimes in which ELT/SHARP can resolve the sphere of influence and nuclear-cluster scales beyond JWST/NIRSpec capabilities. Nearby systems are explicitly presented as a local physics laboratory rather than direct evolutionary analogues of compact active nuclei at high redshift.

QSOspectroscopyhigh-z
Figure 1 from Spectroscopy-informed Deep Learning Searches for Photometric Little Red Dots in JWST Surveys

2026-11-05 · 2611.06026v1 · Research note

Spectroscopy-informed Deep Learning Searches for Photometric Little Red Dots in JWST Surveys

Chenxuan Zhang, Huanian Zhang, Qingwen Wu

Download highlighted PDFarXiv abstract

A two-stage, spectroscopy-informed NIRCam classifier finds LRD candidates beyond standard color selections. Held-out recall/precision are 0.92/0.79, while broad Hα in 10 of 13 grating-observed candidates supports—without confirming—the LRD interpretation of many new selections.

LRDv-shaped SEDspectroscopyhigh-z
Figure 1 from The STARfall pathway: forging intermediate-mass black holes through stellar collisions in dense star clusters

2026-11-04 · 2611.03812v1 · Research note

The STARfall pathway: forging intermediate-mass black holes through stellar collisions in dense star clusters

Filippo Simonato, Manuel Arca Sedda, Taeho Ryu, et al.

Download highlighted PDFarXiv abstract

STARfall semi-analytically models collision-driven very massive stars in dense clusters, predicting 10^3–10^4 M⊙ IMBH seeds under favorable density and timescale conditions. Its Little Red Dot implication is conditional on unresolved systems being sufficiently compact stellar clusters.

LRDQSOhigh-z
Figure 1 from Ly$α$ in Compact Broad-Line Emitters, Including Little Red Dots, Is More Closely Linked to the Host Galaxy than to the Broad-Line Nucleus

2026-11-04 · 2611.03801v1 · Research note

Ly$α$ in Compact Broad-Line Emitters, Including Little Red Dots, Is More Closely Linked to the Host Galaxy than to the Broad-Line Nucleus

Yongda Zhu, Zheng Ma, Xiaojing Lin, et al.

Download highlighted PDFarXiv abstract

In 12 z=4.17–5.54 compact broad-line emitters, Lyα is detected in six and is systematically narrower than broad Hα. Host-SED predictions correlate more closely with observed Lyα than nuclear Hα/UV, although excess Lyα permits nuclear emission.

LRDJWST AGNspectroscopyhigh-z
Figure 1 from Introducing Aurora: A New Black Hole Seeding Model With Explicit Environmental Coupling

2026-11-03 · 2611.01315v1 · Research note

Introducing Aurora: A New Black Hole Seeding Model With Explicit Environmental Coupling

Harry George Chittenden, Darren Croton, Karl Glazebrook, et al.

Download highlighted PDFarXiv abstract

Aurora assigns black-hole seed masses continuously from halo overdensity, radial skewness, and seeding mass. In Millennium/Sage merger trees, this produces an environment-linked minority of seed-dominated massive centrals and enhances predicted quiescence in dense massive haloes near z≈3.1.

overmassive BH
Figure 1 from EMBER: A Little Red Dot Candidate at $z_{\rm spec}=10.36$ in the Seed Black Hole Era

2026-11-03 · 2611.00195v1 · Research note

EMBER: A Little Red Dot Candidate at $z_{\rm spec}=10.36$ in the Seed Black Hole Era

Takumi S. Tanaka, Hollis B. Akins, John D. Silverman, et al.

Download highlighted PDFarXiv abstract

JWST/NIRSpec finds CW-LRD-z10 at zspec=10.361, with a Balmer-limit V-shaped continuum and tentative high-ionization/auroral lines. It is a strong z>10 LRD candidate, but present spectroscopy does not unambiguously establish either broad-line or AGN status.

LRDspectroscopyhigh-z
Figure 3 from Beyond Point Photo-$z$ Estimates: Normalizing Flows for Tomographic $N(z)$ Reconstruction with DESI DR1

2026-11-03 · 2611.00121v1 · Research note

Beyond Point Photo-$z$ Estimates: Normalizing Flows for Tomographic $N(z)$ Reconstruction with DESI DR1

Zhuo Chen, Antoine Rocher, Kwan Chuen Chan, et al.

Download highlighted PDFarXiv abstract

On a spatially independent DESI DR1 test set, conditional normalizing-flow redshift PDFs generally reconstruct tomographic N(z) better than quantile random forests, especially at high redshift; calibration improves several low-z mean-redshift biases but leaves population-transfer and residual-calibration limitations.

QSOspectroscopyhigh-z

2026-11-03 · 2610.33154v1 · Research note

A Composite Rest-Frame UV Spectrum of Galaxies at $5.7 < z < 6.9$: Ionization, Outflows, and Implications for Intergalactic Metal Enrichment

David DePalma, Robert A. Simcoe, Anna-Christina Eilers, et al.

Download highlighted PDFarXiv abstract

A 104-galaxy JWST composite at mean z=6.50 finds ≈180–200 km s⁻¹ blueshifted interstellar absorption. A simple wind-propagation model places most material only 3–9 proper kpc away, challenging bright [O III]-selected galaxies as the dominant source of widespread intergalactic metals.

QSOspectroscopyhigh-z

2026-10-28 · 2610.37564v1 · Research note

Little Red Dots with Broad H$β$ Lines Reveal the Black Hole Mass Function at 7<z<9.5

Anthony J. Taylor, Steven L. Finkelstein, Hollis B. Akins, et al.

Download highlighted PDFarXiv abstract

A systematic JWST/NIRSpec PRISM search finds 20 broad-Hβ emitters at 7<z<9.5, all photometrically/morphologically consistent with LRDs. Completeness-corrected mass-function evolution and inferred BH accretion density are conditional on broad Hβ being a virial black-hole-mass tracer.

LRDspectroscopyhigh-z
Figure 1 from Heavy Seeds and the Multi-scale Fueling of Early Supermassive Black Holes and Little Red Dots

2026-10-28 · 2610.36089v1 · Research note

Heavy Seeds and the Multi-scale Fueling of Early Supermassive Black Holes and Little Red Dots

Junehyoung Jeon, Volker Bromm, Boyuan Liu, et al.

Download highlighted PDFarXiv abstract

Nested sub-pc cutouts suggest that a direct-collapse heavy seed, unlike a stellar-remnant seed in these simulations, can assemble dense nearby gas, undergo bursty super-Eddington accretion, and yield a Balmer-break LRD-like spectrum. This is a model-dependent result, not a demographic measurement.

LRDQSOhigh-z
Figure 1 from $El\ Ascua$: An ultra-luminous, radio-loud, Compton-thick AGN at $z\sim 3.8$ hiding in plain sight revealed by MINERVA multi-band MIRI observations

2026-10-27 · 2610.33155v1 · Research note

$El\ Ascua$: An ultra-luminous, radio-loud, Compton-thick AGN at $z\sim 3.8$ hiding in plain sight revealed by MINERVA multi-band MIRI observations

Aidan P. Cloonan, Edgar P. Vidal, Alexandra Pope, et al.

Download highlighted PDFarXiv abstract

MINERVA/MIRI identifies el Ascua at z~3.8 as a mid-IR-dominant, X-ray-undetected Compton-thick AGN candidate. UV-to-radio SED fitting indicates rapid black-hole growth and a probable AGN radio excess, but obscuration and radio-loudness remain indirect inferences.

obscured AGNQSOspectroscopy
Figure 2 from Local Analogs of Little Red Dots: Clues to the X-ray Weakness

2026-10-26 · 2610.32430v1 · Research note

Local Analogs of Little Red Dots: Clues to the X-ray Weakness

Shi-Jiang Chen, Jun-Xian Wang, Zhen-Ya Zheng, et al.

Download highlighted PDFarXiv abstract

Einstein Probe observations of six z≈0.3 local LRD analogs find an X-weak subgroup whose stacked soft-X-ray constraints favor modest intrinsic coronal weakness plus Compton-thin absorption, rather than the specific unobscured super-Eddington or local Compton-thick geometries tested.

LRDobscured AGNQSOhigh-z
Figure 3 from A Little Red Dot emerging from a nitrogen-rich UV-luminous galaxy with Very Massive Stars

2026-10-22 · 2610.29887v1 · Research note

A Little Red Dot emerging from a nitrogen-rich UV-luminous galaxy with Very Massive Stars

Alberto Torralba, Jorryt Matthee, Rui Marques-Chaves, et al.

Download highlighted PDFarXiv abstract

Medium-resolution JWST/NIRSpec spectroscopy of the single z=6.6 galaxy COLA1 links a very young, VMS-favored UV population, extreme nitrogen enrichment, and LRD-like optical Balmer structure; the proposed evolution into an LRD remains model-dependent.

LRDbroad Balmerspectroscopyhigh-z

2026-10-22 · 2610.28723v1 · Research note

Poisson Clustering and Seed Effect of PBHs: Implications for Microlensing, Gravitational Waves, Little Red Dots and Ultra-Faint Dwarf Galaxies

Bernard Carr, Sebastien Clesse, Juan Garcia-Bellido, et al.

Download highlighted PDFarXiv abstract

This theoretical study argues that Poisson- and seed-driven primordial-black-hole clustering could affect microlensing, merger rates, ultra-faint dwarfs and little red dots, but its PBH-dark-matter interpretation remains sensitive to cluster evolution, Galactic-halo assumptions and non-Gaussian initial clustering.

LRD
Figure 1 from The Balmer Absorber Strength Problem of Little Red Dots

2026-10-22 · 2610.28720v1 · Research note

The Balmer Absorber Strength Problem of Little Red Dots

Hanpu Liu, Eliot Quataert, Bingjie Wang, et al.

Download highlighted PDFarXiv abstract

Photoionization calculations suggest that line emission from an optically thick Balmer absorber can preferentially fill Hα, explaining inverted Hα/Hβ absorption equivalent-width ratios in some LRDs. The result is a proof-of-concept whose inferred absorber properties remain radius- and structure-dependent.

LRD
Figure 3 from Dual and lensed AGN at sub-arcsecond separations uncovered by ERIS

2026-10-21 · 2610.27086v1 · Research note

Dual and lensed AGN at sub-arcsecond separations uncovered by ERIS

M. V. Zanchettin, F. Mannucci, Q. D'Amato, et al.

Download highlighted PDFarXiv abstract

AO-assisted ERIS/SPIFFIER spectroscopy of 34 Gaia Multi-Peak candidates resolves six sub-arcsecond dual AGN and seven lensed quasars, but foreground-star superpositions dominate the non-multiple outcomes and broad-line velocity offsets do not securely measure systemic pair velocities.

obscured AGNspectroscopy

2026-10-16 · 2610.20709v1 · Research note

How Little Red Dots Turn Blue: Evolution of Kelvin-Helmholtz Contracting Black Hole Envelopes and Observational Diagnostics

Zihao Wang, Kohei Inayoshi

Download highlighted PDFarXiv abstract

A time-dependent black-hole-envelope model proposes that little red dots become little blue dots as declining inflow permits Kelvin–Helmholtz contraction. It predicts a distinctive UV–optical color excursion and a 5–50 Myr transition, testable with transitional-source demographics.

LRD
Figure 2 from A heterogeneous set of unusual quasars selected from astrometry and broad-band photometry

2026-10-15 · 2610.19838v1 · Research note

A heterogeneous set of unusual quasars selected from astrometry and broad-band photometry

C. Cheng, K. Valeckas, L. Christensen, et al.

Download highlighted PDFarXiv abstract

Gaia zero-motion selection plus broad-band colours and spectroscopy confirmed 21 quasars among 24 candidates, disproportionately finding BAL quasars in photometrically transitional regions. One low-redshift normal quasar is described as LRD-like, but this is not a high-redshift LRD sample.

LRDQSOspectroscopyhigh-z

2026-10-15 · 2610.19320v1 · Research note

Large-scale Environmental Dependence of AGN Activity Revealed by JWST Pa$α$ Emitters

Danyang Jiang, Linhua Jiang, Shuqi Fu, et al.

Download highlighted PDFarXiv abstract

Using JWST Paα spectroscopy, the authors find that radio-bright AGNs at z=1.1–1.5 occupy denser ∼1.5 pMpc environments than matched controls; density also correlates with accretion indicators, while environmental Paα luminosity functions are elevated and flatter at the faint end.

JWST AGNspectroscopy
Figure 3 from Deep X-ray View of a Distant Protocluster Anchored by a Quasar at $z=6.63$: No Evidence for Enhanced X-ray AGN Activity

2026-10-15 · 2610.19317v1 · Research note

Deep X-ray View of a Distant Protocluster Anchored by a Quasar at $z=6.63$: No Evidence for Enhanced X-ray AGN Activity

Shouyi Wang, Feige Wang, Jinyi Yang, et al.

Download highlighted PDFarXiv abstract

In 865 ks of Chandra imaging, no X-ray AGN is detected among 21 confirmed non-quasar members of the z=6.63 J0910−0414 protocluster. The resulting limits do not establish environmental enhancement, but still allow substantial excess activity.

obscured AGNQSOspectroscopyhigh-z

2026-10-15 · 2610.18968v1 · Research note

The Dance of the Little Red Dots: Spectroscopy of Two Blue Companions at z = 3.9 and 5.5 Reveals Young, Metal-Poor Starbursts Merging with Their LRDs within a Few Hundred Myr

Fabio Pacucci, Pierluigi Rinaldi

Download highlighted PDFarXiv abstract

Spectroscopy of two LRD–blue-companion pairs confirms small line-of-sight velocity offsets and young, metal-poor companion starbursts. Orbital modeling favors a merger for Tango and conditionally for Waltz, while the proposed heavy-seed connection remains interpretive.

LRDspectroscopyhigh-z

2026-10-13 · 2610.15255v1 · Research note

Anisotropic Radiation in Super-Eddington Active Galactic Nuclei: The Responsivity of Broad-Line Regions to Continuum Variability

Feng-Na Fang, Pu Du, Jian-Min Wang

Download highlighted PDFarXiv abstract

Using 175 reverberation-mapping light curves from 128 AGNs, the authors infer that BLR-facing ionizing flux increasingly diverges from the observer-inferred isotropic flux at super-Eddington accretion rates, consistent with—but not uniquely proving—disk-radiation anisotropy.

LRD

2026-10-12 · 2610.13218v1 · Research note

The Population of Type~1 Active Galactic Nuclei in Dark Energy Spectroscopic Instrument. I. Profile-dependent Measurements of the Low-redshift Sample

Zhu-Heng Yao, Wei-Jian Guo, Shuo Zhai, et al.

Download highlighted PDFarXiv abstract

DESI DR1 analysis of 114,754 z≤0.9 type 1 AGNs shows that broad-Balmer profile choice systematically shifts Hβ widths, virial masses, accretion rates, and narrow-line diagnostics, while preserving an apparent continuous NLS1-to-broader-line accretion sequence.

broad Balmerspectroscopy
Figure 2 from Widespread steep X-ray spectra of luminous $z\simeq5.85-7.6$ quasars and their implications for future X-ray surveys

2026-10-08 · 2610.10522v1 · Research note

Widespread steep X-ray spectra of luminous $z\simeq5.85-7.6$ quasars and their implications for future X-ray surveys

A. Tortosa, L. Zappacosta, E. Piconcelli, et al.

Download highlighted PDFarXiv abstract

Across 28 luminous quasars at z=5.85–7.56, X-ray continua are systematically steep, yet show no significant dependence on black-hole growth indicators. The inferred spectral shapes could modestly to severely reduce high-redshift survey count rates.

QSOspectroscopyhigh-z
Figure 1 from MUSE-ALMA Haloes XVI: a census of the condensed baryons in z~0.5 HI absorption-selected galaxies

2026-10-08 · 2610.10117v1 · Research note

MUSE-ALMA Haloes XVI: a census of the condensed baryons in z~0.5 HI absorption-selected galaxies

T. O'Beirne, C. Péroux, M. Zwaan, et al.

Download highlighted PDFarXiv abstract

Across 79 H I absorber-selected galaxies at 0.2<z<1.2, the authors combine multiwavelength data to inventory stars and cold gas, finding broadly consistent indirect H I estimators at small impact parameter but environmentally driven scatter and mass-dependent gas fractions.

QSOspectroscopyhigh-z

2026-10-08 · 2610.08964v1 · Research note

Can LISA See Inside the Little Red Dots?

Samuel Gómez Gómez, Xisco Jimenez Forteza, Carlos Palenzuela, et al.

Download highlighted PDFarXiv abstract

Modelled 10–30 solar-mass EMRIs could let LISA distinguish dense Little Red Dot interiors from vacuum, but detectability is confined largely to low-redshift, low-mass hosts and is dominated by uncertain inspiral rates and idealized gas dynamics.

LRD

2026-10-07 · 2610.08731v1 · Research note

Halo Mass Function Constraints on Early Galaxy and AGN Populations in the JWST Era

Elan Yogeswaren, Robert Schaefer

Download highlighted PDFarXiv abstract

This framework treats JWST massive galaxies, AGN, and UV luminosity functions as host-halo supply tests. It finds that rare-halo abundance predictions depend strongly on high-redshift HMF calibration and assumed baryonic or black-hole mappings, precluding simple source-by-source consistency claims.

JWST AGNhigh-z
Figure 3 from Unveiling the Origins of the Molecular Gas Reservoirs in Recently Quenched Massive Galaxies

2026-10-06 · 2610.06680v1 · Research note

Unveiling the Origins of the Molecular Gas Reservoirs in Recently Quenched Massive Galaxies

E. Savitch, D. Narayanan, D. J. Setton, et al.

Download highlighted PDFarXiv abstract

In Simba, apparently molecular-gas-rich recently quenched galaxies can reflect dust-hidden star formation, a low CO–H2 conversion factor, or temporary quiescence. The model favors no single explanation; rejuvenation is high-redshift-weighted and comparatively uncommon.

obscured AGNhigh-z
Figure 1 from The differences in the Narrow Line Region of nearby QSOs 1 and QSOs 2: II - Signatures of kinetic feedback

2026-10-06 · 2610.03925v1 · Research note

The differences in the Narrow Line Region of nearby QSOs 1 and QSOs 2: II - Signatures of kinetic feedback

Gabriel R. Hauschild-Roier, Thaisa Storchi-Bergmann, Rogério Riffel, et al.

Download highlighted PDFarXiv abstract

In SDSS fibre spectra of 1,541 type-1 and 688 type-2 QSOs at z=0.4–0.5, broad NLR components are more blueshifted in type 1s, consistent with orientation-dependent visibility of faster ionised outflowing gas, but energetics remain model-sensitive.

obscured AGNQSO

2026-10-06 · 2610.03877v1 · Research note

Internal Radiative Feedback Triggers Global Collapse and Direct-Collapse Black Hole Formation in Metal-free Atomic-Cooling Haloes

Masaki Kiyuna, Sunmyon Chon, Kazuyuki Omukai, et al.

Download highlighted PDFarXiv abstract

Cosmological radiation-hydrodynamic simulations suggest that Pop III stars can internally suppress H2 cooling after initial fragmentation, enabling warm-reservoir collapse and rapidly accreting supermassive-star candidates under modest external FUV fields rather than the conventionally required extreme irradiation.

LRDQSO
Figure 1 from Chandra X-ray Spectral Evidence of the Dual AGN Nature of the Gravitational lens MG B2016+112 at z=3.273 with 175 pc separation

2026-10-01 · 2609.38590v1 · Research note

Chandra X-ray Spectral Evidence of the Dual AGN Nature of the Gravitational lens MG B2016+112 at z=3.273 with 175 pc separation

Daniel A. Schwartz, Julia M. Sisk-Reynes, Anna Barnacka

Download highlighted PDFarXiv abstract

Separate Chandra spectra of the two lensed X-ray emitters in MG B2016+112 support the authors’ dual-AGN interpretation: the inner-caustic component is intrinsically absorbed, disfavoring its alternative identification as a highly magnified jet feature.

obscured AGNhigh-z

2026-10-01 · 2609.38430v1 · Research note

Cosmic Collisions I: Optical Morphologies for MIRI-selected galaxies from the PRIMER survey

Gregory Troiani, Allison Kirkpatrick, Leyna Bajaj, et al.

Download highlighted PDFarXiv abstract

JWST/MIRI F770W selection and volunteer classifications of 14,657 PRIMER galaxies at 1<z<3 reveal morphology trends unlike optical/near-IR samples, while wavelength-dependent structure and unresolved mid-IR cores complicate physical interpretation.

obscured AGNspectroscopy
Figure 2 from Caught in the act: diffuse stellar and Ly$α$ emission around a halo-less quasar in the assembling cluster CARLA J0800+4029 at z=2

2026-09-30 · 2609.37445v1 · Research note

Caught in the act: diffuse stellar and Ly$α$ emission around a halo-less quasar in the assembling cluster CARLA J0800+4029 at z=2

Sofia G. Gallego, Simona Mei, Emanuele Daddi, et al.

Download highlighted PDFarXiv abstract

KCWI and HST reveal that CARLA J0800+4029’s dominant Lyα reservoir is tidal and offset from its radio-loud quasar, while a matched-area quasar-halo limit is 3.4 times lower, consistent with spatially redistributed baryons during cluster assembly.

QSOspectroscopyhigh-z
Figure 1 from Connecting the Dots: Prospects for Detecting Multi-Source Inflation through Scale-Dependent and Stochastic Bias of Little Red Dots

2026-09-30 · 2609.36002v1 · Research note

Connecting the Dots: Prospects for Detecting Multi-Source Inflation through Scale-Dependent and Stochastic Bias of Little Red Dots

Peter L. Taylor, Xinyi Chen, Christopher M. Hirata, et al.

Download highlighted PDFarXiv abstract

This paper forecasts whether a purpose-built, wide space survey of LRD clustering at z=4–9 could jointly constrain local fNL and τNL and test the multi-source Suyama–Yamaguchi inequality; its conclusions remain conditional on idealised survey and covariance assumptions.

LRDhigh-z

2026-09-29 · 2609.34903v1 · Research note

Exploring the observed properties of JWST Little Red Dots with cosmological simulations and dust radiative transfer

Saksham Chandna, Fabio Di Mascia, Simona Gallerani, et al.

Download highlighted PDFarXiv abstract

Forward-modelled z=6–9 zoom simulations find that an obscured accreting black hole plus stellar UV emission and dust geometry can produce selected LRD-like colours and compactness, but reproduce only the moderate-Balmer-break subset of observed LRDs.

LRDhigh-z
Figure 1 from SN Helios: A Multiply Imaged Type II Supernova Opening Time-Delay Cosmography beyond redshift of 3

2026-09-28 · 2609.30440v1 · Research note

SN Helios: A Multiply Imaged Type II Supernova Opening Time-Delay Cosmography beyond redshift of 3

Seiji Fujimoto, Conor Larison, Justin D. R. Pierel, et al.

Download highlighted PDFarXiv abstract

SN Helios is a spectroscopically confirmed, strongly lensed Type II supernova at z=3.34. Its predicted 2–6 yr reappearance could enable time-delay cosmography, but current lens-model spread and the absence of a measured delay preclude an H0 result.

obscured AGNspectroscopyhigh-z
Figure 1 from Breaking the Blend: A multi-tracer kinematic decomposition method for IFS data applied to disentangling the AGN outflow and circumnuclear ring in NGC 5728 with JWST

2026-09-25 · 2609.30232v1 · Research note

Breaking the Blend: A multi-tracer kinematic decomposition method for IFS data applied to disentangling the AGN outflow and circumnuclear ring in NGC 5728 with JWST

Oscar Veenema, Niranjan Thatte, Dimitra Rigopoulou, et al.

arXiv abstract

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.

JWST AGNoutflowsspectroscopyobscured AGNlow-z
Figure 1 from A sub-100 pc view at z~5 of a Multiply-Imaged Massive Quiescent Galaxy

2026-09-24 · 2609.28474v1 · Research note

A sub-100 pc view at z~5 of a Multiply-Imaged Massive Quiescent Galaxy

Richard Pan, Danilo Marchesini, Joseph F. V. Allingham, et al.

arXiv abstract

Strong lensing resolves the z=5.18 post-starburst VCQG1 to ~70 pc, revealing an extended stellar body and off-nuclear line-emitting clump. The authors argue these measurements disfavor a simple compaction-plus-unobscured-AGN quenching picture for this individual galaxy.

high-z