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
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.
This theory paper proposes that gas inflow compresses self-interacting dark matter (SIDM) around a pre-existing black hole while an optically thick nuclear disk obscures and reprocesses its emission. It reproduces two representative LRD continua, but does not establish SIDM observationally.
Photospheric fits to 4 absorption-feature LRDs and 82 archival objects yield predominantly super-Eddington ratios. Coupled quasi-star envelope models place black-hole mass caps below local BH–host expectations, but the inference remains model- and host-prior-dependent.
This analytic PBH-cluster framework claims that runaway mergers can reproduce the LRD SMBH mass function with a 1–10% accretion duty cycle while linking overmassive, compact hosts to seed-driven halo evolution; key gas dynamics remain unmodeled.
In 3,566 JWST/NIRSpec galaxies at z=3.0–8.1, UV–optical continuum slopes reveal a continuously populated path from star-forming galaxies to LRDs. The authors interpret it as changing host/BH* continuum contributions, while stressing model-dependent mass-ratio limits.
This modelling study proposes tidal-disruption and quasi-periodic-eruption event rates as population-level probes of LRD black-hole masses. Its predictions depend strongly on assumed stellar cusps, black-hole–stellar-mass relations, and the possibility that most LRDs are obscured.
Cosmological hydrodynamical simulations suggest PBH-seeded hosts can briefly be compact and BH dominated, then become more conventional galaxy–AGN systems when overdense environments accelerate stellar assembly. The result is pathway-dependent rather than a unique prediction for Little Red Dots.
AESOPICA forward-models JWST broad-line selection in 12 cosmological simulations, finding that selection can yield apparently overmassive AGN from several seed scenarios; very light seeds nevertheless require unusually efficient, intermittently super-Eddington growth in the explored models.
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.
Using 98 spectroscopic LRDs at 3<z<7, the authors infer growth from low-mass, relatively under-dense haloes at z>4 to environments and halo masses comparable to galaxies by z≈3.5; proposed structural and spectral changes remain interpretive.
Using AGN-aware fits to JWST spectra, the authors report that non-LRD broad-line AGN shift from elevated observed M_BH/M* above z≈4.5 to the local relation by z≈3.5; LRD host-mass inferences remain substantially less secure.
This theoretical study proposes that rapid, halo-driven accretion produces high-redshift over-massive black holes and possibly Little Red Dots, while virial-shock heating later suppresses growth and moves systems toward local black-hole–stellar-mass scaling.
UV-to-optical fitting of one z=3.55 little red dot, The Cliff, admits a BH* envelope plus low-mass, dusty, metal-poor host. The result depends materially on Balmer-absorption and dust prescriptions, while AGN UV leakage remains unconstrained.
JWST/NIRSpec spectra of two z~6.6 ultra-luminous Lyα emitters reveal broad Balmer-line black-hole masses near 2×10^8 M⊙ and double-peaked Lyα, which the authors interpret as brief post-quasar phases inside relic ionised bubbles.
Dayal cross-compares astrophysical light (~100 M⊙) and heavy (~10^3–10^5 M⊙) seeds (via DELPHI) with cosmological primordial black holes (10^{0.5–6} M⊙; PHANES) against z≈5–10 observables. The only scenario the data rule out is Eddington-limited accretion onto light seeds; high black hole–to–stellar mass ratios (Mbh/M*≈0.3–1) are achievable with PBHs or heavy seeds under super-Eddington growth. Crucially, only PBHs and Eddington-limited heavy seeds can simultaneously recover the observed Mbh, M*, and extremely low host metallicities (Z≤0.01 Z⊙) at z≈7–10. PBHs also predict a distinctive decline of Mbh/M* with increasing halo mass and occupancy of 10^9–10^11 M⊙ halos, motivating a clustering-based test selecting z≈7 systems with Mbh/M*>0.1 and Lbol≈10^{44–46} erg s⁻¹.
Forward-modelled LSST photometry from cosmological simulations can classify simulated black holes as over- or under-massive relative to their host relation at 91–94% accuracy, but transfer and forward-model assumptions remain material obstacles to applying this result to survey galaxies.
JWST/NIRSpec-IFU spectroscopy of the single z=3.55 Little Red Dot The Cliff yields a very low narrow-line metallicity, Z=0.017±0.004 Z⊙, while broad Hβ-based virial estimates place its black hole above local host-scaling expectations.
Extreme-value sampling of fitted black-hole and stellar mass functions predicts median extreme M_BH/M_* = 0.18–0.35 at z=3.5–8.5 (mean ≈0.24), consistent with supplied JWST high-ratio points but not a population-wide relation.
This paper asks whether the newly discussed overmassive black hole galaxies at cosmic dawn can arise naturally from early direct-collapse black-hole formation rather than from a more exotic late-time assembly path. The main result is that a 70,000-solar-mass DCBH formed at very high redshift can grow into a system with the black-hole-to-stellar-mass ratio, metallicity, star-formation rate, and broad spectral properties seen in objects like UHZ1 and GHZ9 by z around 10. The paper matters because it offers a concrete physical channel for the broader JWST overmassive-black-hole population that sits adjacent to the little-red-dot and early-AGN discussion.
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.
Monte Carlo merger evolution can reduce an assumed 0.8–1.0 dex scatter in the z~6 black-hole–stellar-mass relation to the ~0.3 dex local scatter, but the result depends strongly on merger mass ratios and rates; major mergers alone are insufficient.
Joint modelling of broad lines and Chandra non-detections for 14 JWST high-redshift broad-line AGNs favors low-mass, highly super-Eddington black holes with over-cooled coronæ over massive, weakly accreting alternatives, but the inference remains model-dependent and bimodal.
NIHAO simulations suggest that the inferred causal direction of the black-hole mass–velocity-dispersion relation changes across star-forming and quenched phases. Applying a star-forming calibration to 13 z=4.1–10.6 systems lowers their estimated black-hole masses by a median 1.93±0.51 dex.
Cosmological hydrodynamical boxes (50 Mpc)^3 are used to separate merger- from gas-accretion–driven SMBH growth and test feedback choices against SMBH–host coevolution. Seeded at 10^5 Msun, black holes first build up via BH–BH mergers to ~10^7 Msun; only after 7–9 Gyr does accretion reach Eddington, triggering 600–700 Myr bursts that amplify masses by 10^2–10^3 to 10^9–10^10 Msun. AGN-feedback-driven central gas depletion then curtails growth, keeping SMBHs below 10^10 Msun by z=0 and moving systems upward toward the M_BH–M_star relation from below. Implication for JWST little red dots: normal-mass objects are consistent with merger-dominated histories, while overmassive systems require Eddington or super-Eddington accretion episodes.
Using halo merger histories plus empirical prescriptions, the authors project 26 z>6 JWST overmassive SMBHs/LRDs toward lower BH-to-stellar mass ratios by z=0. This is a model-dependent extrapolation, not evidence that individual observed systems will converge.
A data-driven demographic consistency test finds that the abundant faint JWST AGN at z≈5.5 can be explained by moderately elevated black-hole–stellar-mass scaling relations and ∼50% duty cycles, without requiring the most extreme inferred black-hole masses.
JWST/NIRCam decomposition detects extended host emission in 9 of 17 broad-Hα AGN at z≈4–6. Separating point-source light can reduce inferred host masses by 1–2 dex, yielding high BH-to-stellar mass ratios, although unresolved compact hosts remain a viable alternative.
A radiation-hydrodynamic direct-collapse black-hole model can fit one prototypical Little Red Dot spectrum with low residuals while producing Compton-thick obscuration. The result is a model-based explanation, not yet a population-level demonstration that all LRDs are DCBHs.
This analytic PBH-dark-matter scenario argues that PBH shot noise advances low-mass halo collapse and dynamical friction concentrates massive PBHs, potentially assembling UHZ1-like central black-hole masses by z≈10 without super-Eddington gas accretion; viability remains parameter-dependent.
A cosmological radiation-hydrodynamic zoom simulation produces two unusually massive heavy seeds in an overdense, strongly irradiated environment; their growth and transient obscuring disks offer a proposed route to overmassive high-redshift black holes and an LRD-like phase.
Resolved ALMA gas kinematics and JWST stellar light in three ALPAKA discs reveal inner circular speeds exceeding fiducial mass-model predictions. The authors infer missing central mass, plausibly involving bulges, massive black holes, or non-standard inner halo concentrations.
This study tests primordial-black-hole origins for Little Red Dots: direct massive seeds are argued to violate CMB μ-distortion limits, mergers are limited by rare host halos, while accretion of lighter seeds can match QSO1-like properties in restricted parameter space.
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.
BRAHMA mock observations suggest that overmassive, dense-gas-enshrouded AGN can yield AGN-dominated LRD colors and an LRD density of (2.04 ± 0.32) × 10^-4 Mpc^-3 at z=5–8; this is a model-dependent explanation, not a direct detection of the proposed environments.
This paper proposes that feedback-free cluster formation, dry cluster migration, and later wet compaction can jointly make compact, black-hole-hosting LRDs at z=4–8. The central prediction remains a partly untested synthesis because no simulation yet follows all processes together.
Stacking 217 COSMOS-Web little red dots uncovers a faint mean rest-optical extended component: at z=6.45 it has Reff=210±26 pc and F444W=27.7 AB. This ensemble host is compact relative to comparable-mass star-forming galaxies.
Forward modelling of JWST grism Hα morpho-kinematics for 163 z≈4–6 galaxies yields predominantly gas-rich, dark-matter-dominated inner regions. The inferred fractions decline with stellar mass, while the nascent stellar Tully–Fisher relation has substantial scatter.
For 70 JWST broad-line AGN at 3<z<7, the authors infer black holes overmassive relative to local broad-line AGN, with the offset and BH-to-stellar-mass ratio increasing toward high redshift; LRD-rich sample composition contributes substantially.
ApJ-accepted, this paper delivers the first observationally anchored test of how preferential accretion onto the secondary SMBH reshapes binary demographics and gravitational-wave output. Using SDSS close-pair merger rates and empirical SMBH scaling inputs, the authors show that modest differential growth raises mass ratios, converting many minor galaxy mergers into major SMBH mergers and boosting the major-merger fraction by a factor of 2–3. Only ~10% total SMBH mass growth onto the secondary brings the predicted nanohertz gravitational-wave background into agreement with PTA measurements and accelerates the first continuous-wave binary detection. The effect is even stronger for LISA-era binaries in gas-rich, higher‑z environments, offering a path toward the rapid build-up of overmassive black holes seen by JWST.
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.
Deep JWST/NIRSpec spectroscopy of the z=6.68 Little Red Dot Irony supports an AGN viewed through dense, stratified, multi-component gas: Balmer absorption covers both continuum and broad-line emission, while black-hole inferences remain profile-dependent.
BlackTHUNDER presents JWST/NIRSpec IFU spectroscopy of UNCOVER_20466 (z=8.50), confirming its LRD nature and an overmassive central black hole. Balmer decrements indicate little dust, yielding an Hβ-based bolometric output and Eddington ratio only ~10% of earlier estimates—consistent with a currently subdued/dormant phase. Strong Lyα (f_esc ≈ 30%) and an extreme [O III]4363/Hγ imply AGN photoionization with ultra-dense gas (n_e ~ 10^7 cm^-3). The source sits on local M_BH–σ_* and M_BH–M_dyn relations and is compatible with growth from a heavy seed (~10^3 M⊙), marking it as a likely progenitor core of a later galaxy.
Strong lensing plus JWST/NIRSpec IFS resolves narrow Hα kinematics and spectroastrometric shifts in the lensed Little Red Dot Abell2744‑QSO1 at z=7.04, enabling a direct rotation curve from ~10–200 pc. The curve is Keplerian and rules out compact extended mass profiles (e.g., MW‑like nuclear star cluster, Plummer, or a DM cusp), implying a central point mass of order 5×10^7 M⊙ consistent with Balmer‑line virial estimates. The inferred stellar content is minimal, with MBH/M* > 2, pointing to a near‑“naked” black hole in a pristine environment. This result validates virial BH masses for LRDs at the EoR and captures a massive BH seed in its earliest growth phase.
Photometric SED decomposition of 121 variability-selected HUDF nuclei using HST+JWST (0.2–4.8 μm) isolates stellar and AGN components and estimates MBH from L5100 via local scalings. AGN contributions are significant in 26 sources across 0<z<7, including a zphot=6.74 object with a lower limit log10(MBH/M⊙)>7.36. In the MBH–M* plane, low‑z sources align with local relations while higher‑z systems—and two z<1 dwarf hosts flagged as IMBH candidates—are increasingly overmassive. A NIRISS‑confirmed BL‑AGN exemplifies successful recovery, with the AGN providing ≈95% of the flux in at least one band, underscoring accelerated early BH growth relative to hosts.
Analyzing recent JWST reports of ~100× overmassive black holes at z>5, the authors show that if such BHs are common, the global black hole mass density at z≈5 would already rival today’s value—unless the overmassive systems are rare or accrete with very high radiative efficiencies (implying rapid spin). Tracking representative z≈5 detections forward using average growth rates from modern models keeps them overmassive relative to the local Mbh–M⋆ relation. To land within the local scatter by z≈0, these BHs must grow at least an order of magnitude more slowly than expected. This creates tension with the rapid early growth needed to assemble them and complicates standard expectations for quasar feedback on galaxies.
The authors run 3D Monte Carlo radiative transfer to test how resonance, Raman, and Thomson scattering sculpt Balmer lines in Little Red Dots. Resonance scattering in an n=2–populated H I medium drives strong departures from Case B and distinct Hα vs Hβ shapes, but Hβ is funneled into Paα, preventing broad Hβ wings. Raman scattering of higher Lyman-series emission can explain Hα/Hβ wing-width ratios ≳1.28, whereas Ramanization of a UV continuum is disfavored by the near-constant FWHM across transitions. Thomson scattering with Te≈10^4 K and electron column ≈10^24 cm−2 reproduces the ≳1000 km s−1 wings and implies virial BH masses can be overestimated by ≳10 if widths are taken at face value.
JWST/NIRCam narrow–medium–wide imaging selects [O III] 5007 emitters at z≈7.08 around ULAS J1120+0641 across two 4.4 arcmin² fields, revisiting a site previously deemed underdense. The team finds 22 candidates near the quasar redshift, demonstrating a strong overdensity relative to field expectations, and sums the stellar+gas masses of the host plus neighbors with incompleteness corrections to estimate the merger-fed growth budget. Even if the black hole ceases accretion, the system is projected to retain an elevated MBH/M* ≳2.5% by z=0, far above the local relation. This implies some descendants could hide as quiescent black holes in faint galaxies at low redshift.
Proposes an SIDM-driven seeding pathway for JWST little red dots in which gravothermal core collapse, sped up by central baryons, makes a tiny seed that grows first via baryonic Eddington accretion and then rapidly through dark Bondi inflow of SIDM. Demonstrates that black holes can reach ~10^7 Msun within ~500 Myr after the formation of ~10^9 Msun halos at z≈4–11, with most of the final mass supplied by dark matter rather than gas. Fluid simulations with and without a Plummer-fit baryonic potential show that baryons substantially shorten the collapse timescale and establish conditions for efficient dark-sector Bondi growth. The framework naturally explains the overmassive BH-to-stellar ratios in LRDs and links them to SIDM cross sections consistent with galaxy-scale structure data.
Uniform ALMA [CII] 158 μm size measurements for a curated sample of 22 z≈6 quasars show their hosts are systematically compact, with a median Re≈1.58 kpc versus 2.26 kpc for main-sequence SFGs measured in the same line. The hosts also have elevated MBH/M* and, for the most compact systems, reduced cold-gas content and sizes akin to massive quiescent galaxies at z≈4–5. Simple evolution over a gas-depletion timescale moves them toward the local MBH–M* relation as stellar mass builds. The compact, gas-poor subset likely marks the late stage of rapid BH growth and are prime progenitors of the first quiescent galaxies.
Reports a broad-line Little Red Dot at z=5.077 (JADES-GS+033223.41-275404.5/159717) with NIRSpec MSA+IFU, revealing multi-component Hα including two broad Gaussians. A virial black hole mass of log(MBH/M⊙)=7.65 and a narrow [O III] λ5007-based dynamical mass of log(Mdyn/M⊙)=9.1 imply a BH overmassive relative to its host. The source sits in a 7-kpc pool of ionized gas with three neighbors (a satellite, a possible satellite/gas cloud, and a tentatively detected spatially detached outflow). A deep rest-frame Hα absorber (deeper than the continuum; v=-13 km s−1, σ=120 km s−1) appears in G395H but not G395M, with tentative EW variability over two rest-frame months (2.6σ), underscoring resolution- and time-dependent incidence of absorbers in LRDs.
Using THESAN-ZOOM zoom-ins, the authors assign black-hole masses by assuming the M_BH–M_dyn relation is fundamental and then compare to JWST-selected AGN and JADES host properties at z>3. This simple prescription reproduces the observed distribution of “overmassive” black holes relative to local M_BH–M_* relations, with M_BH/M_* declining from ~0.1 at M_*≈10^6 Msun to ~0.01 at M_*≈10^10.5 Msun. The trend naturally follows the high dark-matter and gas fractions of low-mass galaxies—f_DM and f_gas decrease with M_* and show little evolution to z≈3—yielding small M_*/M_dyn and thus large apparent BH offsets; Prospector-inferred f_gas for 48,022 JADES galaxies (3<z<9) agrees with the simulations. A caveat is that BH growth and feedback are not modeled live, so full BH–galaxy co-evolution is not captured.
JWST/NIRSpec IFU datacubes of six extremely red quasars at z=2.4–2.9 plus two lower‑z dust‑obscured quasars are decomposed across wavelength to isolate host‑galaxy continua and morphologies. The hosts are compact (Re = 1.4–2.9 kpc) with stellar masses 10^10.6–10.9 Msun, and many targets show quasar–host centroid offsets of 0.4–1.3 kpc suggestive of post‑merger dynamics or patchy obscuration. ERQs sit 0.5–2 dex above the local MBH–M* relation and appear more compact, lower‑n, and lower‑mass than HST‑based inferences, underscoring the leverage of IFU‑based continuum separation. The authors note that the apparent over‑massive black holes may reflect selection bias.
Using NIRSpec medium/high-resolution data and line-free photometry, the authors isolate five narrow-line LRDs at z≈5 (H-alpha FWHM ≈250 km/s; one ≈475 km/s) from 32 LRDs with H-alpha coverage, and show that about 20% of color-selected LRD candidates fake a V-shape continuum via strong lines. Relative to normal star-forming galaxies, these objects have higher H-alpha widths and luminosities but smaller equivalent widths. SED fits allow either dusty, compact, high-M* and high-SFR galaxies or low-mass AGN with MBH≈10^5–10^6 Msun, plausibly in an early, super-Eddington phase; the BHs are slightly overmassive vs MBH–M* yet consistent/undermassive vs MBH–sigma and MBH–Mdyn within large errors. Nearly half of high‑z broad-line AGN show V‑shape SEDs, underscoring that LRD-like photometry does not uniquely imply broad-line activity.
JWST/NIRSpec-IFS dissects the triply imaged Little Red Dot Abell2744-QSO1 at z=7.04, isolating the narrow Hβ to map line ratios. [OIII]5007 is exceptionally weak—[OIII]/Hβn ≈ 0.6 within r<150 pc and <0.32 at 150–300 pc—implying Z ≈ 8×10^-3 Z⊙ centrally and Z<6×10^-3 Z⊙ in the extended gas, while broad Balmer lines/variability yield MBH ≈1.5×10^7 M⊙ in a host with Mdyn ≈10^7.1–10^8 M⊙. This places a massive black hole in an almost pristine, very low-mass galaxy only ~700 Myr post-Big Bang. The chemistry and mass budget strain heavy-seed or super‑Eddington growth paths, motivating alternatives such as primordial black-hole seeds that remain to be fully tested.
Using JWST/NIRSpec IFU stellar kinematics plus archival long-slit data, the authors model the compact elliptical NGC 4486B and resolve a double nucleus with a velocity-dispersion peak offset from the photometric center. Axisymmetric Schwarzschild modeling of the full LOSVD yields M_BH = 3.6 ± 0.7 × 10^8 M_sun and a host ratio M_BH/M_* ≈ 4–13%, firmly placing the black hole in the overmassive regime. Dark matter within 1 kpc is weakly constrained (M_DM/M_* < 0.5), and the inferred M_BH is unchanged with or without a halo. The system’s location deep in Virgo supports a stripped-core origin, with the caveat that non-equilibrium double-nucleus dynamics are not modeled, so the mass may be a lower limit.
Orbit-based dynamical models of Segue 1 favor a central intermediate-mass black hole of 4 ± 1.5 × 10^5 M⊙, reproducing the stellar kinematics with a near-isotropic orbital structure. Zero–black-hole models both fit worse and require an extremely compact dark halo (scale radius ~100 pc) plus highly radial stellar orbits, while the BH model is also supported by a central rotation spike of 9.0 ± 2.4 km s−1. The tracer profile is built from number counts with tidal-stream subtraction and deprojection, and the stellar mass-to-light ratio remains poorly constrained, underscoring non-stellar mass dominance. Taken together, Segue 1 looks like a tidally stripped nuclear remnant and a nearby analog of Little Red Dots with overmassive black holes.
Using JADES spectroscopy, the authors assemble a uniform census of 34 broad-line (Type 1) AGN spanning 1.5<z<9 with virial black-hole masses of 10^6–10^9 M⊙ and bolometric luminosities down to 10^43 erg s^-1, generally at sub-Eddington rates (<0.5 L_Edd). These AGN are typically in low-mass (M⋆≈10^8 M⊙) hosts whose black holes are overmassive relative to the local M_BH–M⋆ relation yet consistent with the local M_BH–σ⋆ relation, enabling a view of how these scalings emerge across cosmic time. The team shows that standard narrow-line diagnostics would miss many counterparts—especially at low metallicity or with attenuated/soft ionizing continua—complicating Type 2 selection. They also find strong cosmic-variance sensitivity in the UV luminosity function and rule out electron/Balmer scattering as the origin of broad Balmer components, arguing BH masses are not severely overestimated.
This letter benchmarks secure dynamical black hole masses in a z~2 lensed quiescent galaxy and six local red‑nugget relics against recent 4<z<11 AGN, quasar, and Little Red Dot samples on the M_BH-M_star and M_BH-sigma_* planes. The relics and the z~2 quiescent system land on both the local bulge M_BH-M_star relation and the 4<z<7 Pacucci et al. relation, while luminous QSOs and broad-line AGN follow Pacucci et al. more closely and LRDs scatter across all three; on M_BH-sigma_* most sources sit above the local median except the lensed system. The authors argue the bulge relation was already in place at high z and that differing evolutionary pathways—compact-core assembly by z~2 followed by dry-merger stellar-mass growth versus ongoing BH and star formation in AGN—govern positions on scaling planes. Given large systematics in single‑epoch high‑z masses, they emphasize dynamical detections in relics and strongly lensed galaxies as a complementary, less biased probe of early scaling relations.
BlackTHUNDER re-analyzes JWST/NIRSpec-IFS G395H data for the Little Red Dot Abell2744-QSO1 at z=7.04, focusing on the Hα region. The Hα profile is distinctly non-Gaussian, requiring at least two broad Gaussians plus a narrow component, and shows strong rest-frame Balmer-line absorption (EW ≈22 Å) centered at the systemic velocity of the broad line; the absorber’s dispersion (σ_abs ≈110 km s⁻¹) matches that inferred from the Balmer break, arguing for a long‑lived, non-flowing structure. An Hα-based virial mass of log(MBH/M⊙) ≈7.2 and a deconvolved narrow-line width σ_n ≈22 km s⁻¹ yield MBH/Mdyn = 0.15–1.2, confirming an overmassive black hole with limited room for a host galaxy. The revised mass implies high accretion, λ_Edd ≈0.7–1.6 (potentially super‑Eddington at the low‑mass end), tying Balmer-break strength directly to Balmer-line absorption in LRDs.