Weekly issue

Week 45, 2025

Nov 3–9, 2025

Week 45, 2025 includes 6 curated papers, centered on QSO, spectroscopy, high-z.

2511.05029v1

Discovery of an X-ray Luminous Radio-Loud Quasar at $z=3.4$: A Possible Transitional Super-Eddington Phase

Sakiko Obuchi, Kohei Ichikawa, Satoshi Yamada, Nozomu Kawakatu, Teng Liu, Naoki Matsumoto, Andrea Merloni, Kosuke Takahashi, Ingyin Zaw, Xiaoyang Chen, Kazuhiro Hada, Zsofi Igo, Hyewon Suh, Julien Wolf

Theme match 4/5

Digest

Multiwavelength follow-up identifies eFEDS J084222.9+001000 (ID830) at z=3.4351 as the most X-ray luminous radio-loud quasar in the eFEDS field. It shows log L0.5–2keV=46.20±0.12 with a steep Γ=2.43±0.21, radio detections (FIRST 1.4 GHz; VLASS 3 GHz), modest reddening AV=0.39±0.08, Lbol,3000=(7.62±0.31)×10^46 erg s−1, and MBH=(4.40±0.72)×10^8 M⊙ from Mg II. The inferred Eddington ratios are λEdd,UV=1.44±0.24 and λEdd,X=12.8±3.9, and the source is unusually X-ray bright for its UV luminosity with αOX=−1.20 (−1.42 after jet-linked correction), unlike super-Eddington quasars and little red dots that typically have αOX<−1.8. The authors argue ID830 is a transitional post-burst phase where a prominent jet and vigorous X-ray corona coexist as the system evolves from super- to sub-Eddington accretion.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1: Locate ID830 on the L0.5–2 keV–redshift plane to see it uniquely occupies the extreme luminosity region targeted by the selection, underscoring its rarity within the eFEDS-WERGS sample.
Figure 2: Inspect the eROSITA X-ray spectrum and best-fit components to verify the steep photon index (Γ≈2.4) and the lack of heavy absorption, key to the X-ray-bright, soft-state interpretation.
Figure 3: Compare SDSS+MOIRCS spectra to the reddened quasar template to read off AV≈0.39 and how the extinction correction sets Lbol,3000 used for λEdd,UV and for the αOX evaluation.
Figure 4: Use the PyQSOfit line decompositions—especially Mg II—to see the measured line width and continuum placement that yield MBH≈4.4×10^8 M⊙ and underpin the Eddington-ratio estimates.

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2511.05036v1

A deep X-ray look to the most obscured quasar at z~3.6 and its environment

I. Villani, L. Zappacosta, E. Piconcelli, M. Ginolfi, F. Ricci, F. La Franca, F. Arrigoni-Battaia, A. Bongiorno, S. Cantalupo, S. Carniani, F. Civano, A. Comastri, F. Fiore, R. Maiolino, L. Pentericci, C. Ricci, R. Schneider, R. Valiante, C. Vignali, F. Vito

Theme match 3/5

Digest

A 280 ks Chandra view of the Hot DOG quasar W0410-09 (z=3.631) reveals Compton-thick obscuration (N_H > 10^24 cm^-2) and an intrinsic hard X-ray luminosity L_2–10 > 10^45 erg s^-1, making it among the most luminous obscured QSOs beyond z > 3.5. In its overdense environment of 19 Lyα emitters within 300 kpc and ±200 km s^-1, no sources are individually detected in X-rays, but a rest-frame 6–7 keV stack shows a ~3σ Fe Kα signal, implying hidden AGN; the LAE AGN fraction is f_AGN^LAE = 5^{+12}_{-4}% and could reach ~35% if these obscured components are included. The relatively compact 30 kpc Lyα nebula compared to ~100 kpc structures around unobscured QSOs is attributed to heavy nuclear obscuration suppressing ionizing UV, consistent with a transitional blow-out phase. This system links extreme accretion and obscuration from nuclear to circum-galactic scales during early massive-galaxy assembly.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1: Inspect the ACIS-S 0.3–7 keV image and extraction regions to see the isolated X-ray point source at W0410-09 and the lack of nearby X-ray detections among LAEs after wavdetect masking.
Figure 2: Compare empirical fits (power law, absorbed power law, reflection-dominated) to visualize the hard-band curvature and residuals that motivate a heavily obscured/reflection component.
Figure 3: Examine BORUS/BorSphere torus fits separating transmitted and reflection components; note how CT-level N_H and geometry affect the continuum and reflection strength, setting the intrinsic L_2–10.
Figure 4: Use MYTorus decomposition (transmitted, Compton-scattered, line components) to evaluate CT obscuration and the Fe Kα line behavior that anchors the inferred column density.

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2511.06085v1

A JWST/NIRSpec Integral Field Unit Survey of Luminous Quasars at z ~ 5-6 (Q-IFU): Rest-frame Optical Nuclear Properties and Extended Nebulae

Weizhe Liu, Xiaohui Fan, Huan Li, Richard Green, Jaclyn B. Champagne, Xiangyu Jin, Jianwei Lyu, Maria Pudoka, Wei Leong Tee, Feige Wang, Jinyi Yang, Yongda Zhu, Nayera Abdessalam

Theme match 2/5

Digest

Q-IFU uses JWST/NIRSpec IFU to obtain rest‑frame optical spectra for 27 luminous quasars at z ~5–6, measuring nuclear properties and searching for extended nebulae. Hβ yields log(MBH/M⊙) ≈ 8.6–9.7 and λEdd ≈ 0.1–2.6, broadly consistent with Hα; relative to luminosity-matched lower‑z samples the median MBH is slightly smaller and λEdd slightly larger, but differences are within statistical uncertainties. [O III] λ5007 EW tracks Lbol and λEdd as at low z and most sources lie on EV1 planes, while a subset shows enhanced, blueshifted [O III] signaling fast outflows. Six objects exhibit spatially extended [O III] with merger‑like or turbulent, clumpy kinematics, including tentative evidence that quasar radiation is reshaping a companion’s ISM in the system with the largest nebula.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1: Check where the 27 targets sit in M1450–z space relative to the literature sample to gauge luminosity matching and the two redshift windows used for grating placement.
Figure 2: Inspect rest‑optical–based systemic redshifts versus UV‑line redshifts to quantify typical Δz offsets that impact outflow blueshift measurements and BH‑mass calibrations.
Figure 3: Compare the Q‑IFU composite to the luminosity‑matched z~1.5–3.5 Shen sample—focus on Hβ profile, Fe II strength, and [O III] EW to see the EV1 placement and Baldwin‑type trends at z~5–6.
Figure 4: Read the Lbol–MBH diagram with Eddington‑ratio lines to see the distribution (log MBH ~8.6–9.7; λEdd up to >1) and the mild shift toward higher accretion rates versus lower‑z quasars, plus context from ASPIRE and SDSS.
Appendix Fig. 11: Use the individual Hβ+[O III] (and Hα where available) fits to verify multi‑component decompositions, blueshifted [O III] wings, and the tied broad‑line kinematics used for MBH estimates.

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2511.02902v1

A close look at the black hole masses and hot dusty toruses of the first quasars with MIRI-MRS

Sarah E. I. Bosman, Javier Álvarez-Márquez, Frederick B. Davies, Klaudia Protušová, Joseph F. Hennawi, Jinyi Yang, Benedetta Spina, Luis Colina, Xiaohui Fan, Göran Östlin, Fabian Walter, Feige Wang, Martin Ward, Almudena Alonso Herrero, Aaron J. Barth, Silvia Belladitta, Leindert Boogaard, Karina I. Caputi, Thomas Connor, Dominika Ďurovčíková, Anna-Christina Eilers, Alejandro Crespo Gómez, Jens Hjorth, Hyunsung D. Jun, Danial Langeroodi, Weizhe Liu, Alessandro Lupi, Chiara Mazzucchelli, John P. Pye, Pierluigi Rinaldi, Paul van der Werf, Marta Volonteri

Theme match 2/5

Digest

JWST/MIRI-MRS spectra of the four most distant luminous type-1 quasars (J0313−1806, J1342+0928, J1007+2115, J1120+0641; z=7.08–7.64) deliver rest-frame optical/IR broad H-alpha, Pa-alpha, and Pa-beta, yielding consistent virial masses MbH=(4–15)×10^8 Msun that agree with prior Mg II while C IV remains biased. The hydrogen-line ratios depart from case A/B in the same way as at z<3, pointing to similar BLR conditions. A hot-dust torus is unambiguously detected in all four; SKIRTOR fits favor face-on viewing with opening angles 40–60 deg and torus dust masses 1–4×10^6 Msun (0.2–7% of host dust), implying depletion in ~5 Myr at observed accretion rates. Together these results indicate z>7 quasar BH masses and accretion are not fundamentally different from z<3 counterparts, yet are still too large to arise from stellar-remnant seeds if epsilon=0.1.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1: Use the full MRS spectra to verify line identifications (H-alpha, Pa-alpha, Pa-beta) and the rising near-IR continuum from hot dust; note Channel 4 is missing for J1342+0928 due to cosmic-ray showers, which explains gaps at the reddest wavelengths.
Figure 2: Inspect the H-alpha multi-component fits and FWHM—J0313−1806 and J1120+0641 show the broadest components, anchoring the largest virial widths; for J1342+0928, residual CR artifacts limit the decomposition to a single broad component.
Figure 3: Compare single-epoch MbH across five tracers; H-alpha/Pa-alpha/Pa-beta cluster within the intrinsic scatter and align with Mg II, while C IV remains systematically offset even after blueshift correction—this underpins the paper’s mass-robustness claim.
Figure 4: Read the Balmer–Paschen flux ratios against Cloudy tracks; the positions away from case A/B and not along an extinction vector argue for BLR density/ionization effects similar to those at z<3, supporting the non-evolving BLR conditions conclusion.

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2511.02523v1

Dynamical Masses and Radiative Transfer Modeling of HD 698: a Be Binary in Evolutionary Transition

Ilfa A. Gabitova, Alex C. Carciofi, Tajan H. de Amorim, Mark Suffak, Anatoly S. Miroshnichenko, Sergey V. Zharikov, Amanda C. Rubio, Steve Danford, Alicia N. Aarnio, Peter Prendergast, Richard J. Rudy, Richard C. Puetter, R. Brad Perry, Aldiyar T. Agishev, Nadezhda L. Vaidman, Serik A. Khokhlov

Theme match 2/5

Digest

The authors combine high‑resolution spectroscopy, long‑baseline interferometry, and HDUST radiative‑transfer modeling to solve the orbit and decompose the SED of the Be binary HD 698 (V742 Cas). Counter‑phased RVs give a circular P=55.927±0.001 d orbit with M_Be=7.48±0.07 M_sun and M_comp=1.23±0.02 M_sun at a dynamical distance of 888±5 pc, with broad Hα wings tracing the Be star and narrow metallic lines the companion. The SED requires E(B−V)=0.321±0.016 and a decretion disk with ρ0≈5×10^-12 g cm^-3 and n=3.0, while the companion is luminous and inflated (T_eff≈10 kK, R≈13.1 R_sun, log L/L_sun=3.19) contributing L_comp/L_Be≈0.3. Spectral mismatches point to a hydrogen‑poor, CNO‑processed atmosphere, marking HD 698 as a Be+bloated OB system caught in the short post‑mass‑transfer phase before the sdO/B stage.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1: Inspect the trailed spectra around 4450–4545 Å, 4815–4890 Å, and 6520–6690 Å to see the anti‑phased motion: broad Hα wings track the Be star while narrow metallic lines trace the slowly rotating companion, emphasizing the stark v sin i contrast used for RV extraction.
Figure 2: The phase‑folded RV curves and fits yield the circular 55.927 d solution and mass ratio; check the ~1.7–2.1 km s^-1 RV uncertainties and residuals to appreciate the dynamical precision behind M_Be and M_comp.
Figure 3: The Be‑disk surface‑density map shows tidal truncation and two spiral arms in a ~50‑day binary; compare the Roche geometry and the ~25.6 R_eq separation to how such structures could drive the observed Balmer‑line morphology and variability.
Figure 4: SED decomposition (Be star+disk vs. companion) illustrates E(B−V)=0.321, the disk contribution, and the companion’s ~30% flux share; use the residuals panel to locate wavelengths where composition/disk physics may be incomplete.

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2511.01344v1

BALNet: Deep Learning-Based Detection and Measurement of Broad Absorption Lines in Quasar Spectra

Yangyang Li, Zhijian Luo, Shaohua Zhang, Du Wang, Jianzhen Chen, Zhu Chen, Hubing Xiao, Chenggang Shu

Theme match 2/5

Digest

Presents BALNet, a 1D-CNN + Bi-LSTM that detects and measures C IV BAL troughs directly along quasar spectra, trained on SDSS DR16-based mocks spanning 1.5<z<5.7. On tests it recovers troughs with 83.0% completeness and 90.7% purity (F1=86.7%) and classifies BAL quasars at 90.8% completeness/94.4% purity, with predicted velocities closely matching labels. Applied to DR16, BALNet finds ≥1 BAL trough in 20.4% of spectra, with >25% newly identified and 8.8% redshifted systems—boosting inflow candidates and a less biased BAL census. Caveat: some narrow/weak absorption is still missed.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1: Compare observed vs simulated distributions of the number of C IV BAL troughs per spectrum to judge whether the mock set reproduces multi‑trough incidence and avoids overproducing simple single‑trough cases.
Figure 2: Inspect the mock‑construction pipeline and label vector; verify how real unabsorbed spectra are combined with randomly placed BAL regions and whether the setup can encode redshifted (inflow) as well as blueshifted features.
Figure 4: Examine how the 1165‑pixel input is downsampled to a 387‑element probability vector (kernel_size=7, stride=3) and whether this resolution sets a practical floor on detectable trough width—relevant to the stated misses of narrow/weak absorption.
Figure 3: Review the LSTM gating schematic to understand how sequential context along the spectrum is modeled, which underpins the reported agreement between predicted velocities and labels.