Weekly issue

Week 18, 2026

Apr 27 – May 3, 2026

Week 18, 2026 includes 5 curated papers, centered on spectroscopy, JWST AGN, high-z.

2605.00763v1

Life After the Quasar: Overmassive Black Holes and Remnant Ionised Bubbles in and Around Two z~6.6 Galaxies

Romain A. Meyer, Pascal A. Oesch, Callum Witten, Richard S. Elllis, Sarah E. I. Bosman, Fred Davies, Alyssa B. Drake, Nicolas Laporte, Jorryt Matthee, Fabian Walter

Theme match 5/5

Digest

JWST/NIRSpec IFU G235M/G395M spectroscopy of the ultra-luminous z~6.6 Lyα emitters COLA1 and NEPLA4 reveals clear broad Balmer emission, implying SMBHs of roughly 2×10^8 M☉ in systems whose stellar masses are only ~10^9 M☉. That puts both objects at extreme BH-to-stellar-mass ratios of about 0.1-0.2, hundreds of times above the local BH-host relation, while the inferred stellar populations are very young and dominated by recent assembly. The paper argues that this mismatch, together with the rare double-peaked Lyα profiles, is best explained if both galaxies are observed shortly after a quasar phase: a recently active, now-fading AGN could have built the BH early and maintained the large, highly ionised bubble needed for Lyα transmission. In that picture, COLA1 and NEPLA4 are post-quasar galaxies that link JWST-selected AGN to faint high-redshift quasars and suggest episodic quasar activity may help create large ionised regions deep into reionisation.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1. Use Figure 1 for the core observational evidence: the Hβ+[O III] and Hα+[N II] line-complex fits for NEPLA4 and COLA1 show the broad Balmer components that drive the AGN identification and single-epoch virial BH-mass estimates. This is the cleanest figure for demonstrating that these are not ordinary star-forming Lyα emitters but systems with directly inferred massive black holes.
Figure 2. Use Figure 2 because it concentrates the paper’s main interpretation into one multi-panel diagnostic. The left and middle panels contrast the BH growth histories required to reach ~2×10^8 M☉ by z=6.6 with the much more recent stellar buildup from the BAGPIPES star-formation histories, while the right panel shows how extreme COLA1 and NEPLA4 are relative to JWST AGN, high-redshift quasars, and the local BH-stellar-mass relation.

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2604.25991v1

The GlimmIr: Spectroscopic Variability in a z~7 LRD Indicates Rapid Changes in Both the Narrow and Broad Line Regions

Erini Lambrides, Taylor A. Hutchison, Rebecca L. Larson, Pablo Arrabal Haro, Casey Papovich, Weida Hu, Nikko J. Cleri, Steven L. Finkelstein, Jonathan R. Trump, Pablo G. Perez-Gonzalez, Bingjie Wang, Dale D. Kocevski, John Chisholm, Amy Secunda, Sarah E. I. Bosman, Hollis Akins, Mitchell Karmen, Mark Dickinson, Volker Bromm, Bren E. Backhaus, Marco Chiaberge, Olivia R. Cooper, Yukta Ajay, Guillermo Barro, Danielle A. Berg, Jenna Cann, M. C. Cooper, Norman A. Grogin, Michaela Hirschmann, Marc Huertas-Company, Jeyhan S. Kartaltepe, Anton M. Koekemoer, Ray A. Lucas, Arianna S. Long, Roberto Gilli, Colin Norman, Andrew F. Ptak, Chris T. Richardson, Jane R. Rigby, Brittany N. Vanderhoof, L. Y. Aaron Yung, Jorge A. Zavala

Theme match 4/5

Digest

This paper reports the first spectroscopic variability detected in a z~7 little red dot, GlimmIr, by comparing deep JWST/NIRSpec F290LP/G395M spectra from THRILS and C3PO taken 99 days apart, or about 13 rest-frame days. The source shows roughly 30% changes in the continuum and broad-line flux and a 42% change in [OIII]5008, and the authors argue these differences are not caused by slit placement, pathloss, or simple flux-calibration offsets; prism data from RUBIES and CAPERS independently support the multi-epoch variability. Under an accreting-black-hole interpretation, the rapid [OIII] response means some narrow-line gas beyond the broad-line region must have a direct view of the ionizing continuum. That in turn argues for covering fractions below unity and against [OIII] being dominated by ordinary host-galaxy processes, with implications for how black-hole properties are inferred in LRDs.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1 is the anchor figure for the paper because it shows the two deep G395M epochs directly in both 2D and 1D, making the continuum, broad-line, and [OIII] differences immediately visible. The ratio panel is especially important because it localizes where the variability is strongest, and the slit-overlay inset supports the paper's argument that different MSA placements are not driving the result.
Figure 2 is the strongest corroborating figure because it brings in the CAPERS and RUBIES prism spectra and shows that the continuum and [OIII] changes persist across additional epochs and observing programs. This matters for the paper's core claim that GlimmIr is genuinely spectroscopically variable rather than an outlier created by one specific reduction or one pair of observations.
Figure 4 gives the clearest comparison to other repeat-observed sources and shows that GlimmIr is an outlier in brightest-line flux ratio relative to the comparison sample. It is the best synthesis figure for demonstrating that the measured variability is larger than the level of repeat-observation scatter the authors consider plausible from ordinary systematics.
Figure 5 carries the paper's main physical interpretation by linking the observed variability to direct sight-lines from the accretion source to gas outside the broad-line region. This is the figure that best explains why the authors infer a broad-line-gas covering fraction below 100% and why the narrow-line emission cannot be treated as fully screened from the central engine.
Figure 6 is the most important caveat-handling figure because it tests whether pathloss corrections could mimic the observed spectral differences. By showing that the continuum and line changes exceed the pathloss-induced shifts across the relevant spectral regions, it underpins the conclusion that the variability is astrophysical and affects both the broad- and narrow-line emitting zones.

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2605.00822v1

PEARLS: Two Distinct Populations of AGN Hosts Moving Between Star Formation and Quiescence

Gibson B. Bowling, Rafael Ortiz, S. P. Willner, Seth H. Cohen, Timothy Carleton, Rogier A. Windhorst, Rolf A. Jansen, Christopher N. A. Willmer, W. Peter Maksym, Anton M. Koekemoer, Madeline A. Marshall, Rosalia O'Brien, Payaswini Saikia, Massimo Ricotti, Jordan C. J. D'Silva, Dan Coe, Christopher J. Conselice, Jose M. Diego, Simon P. Driver, Brenda L. Frye, Norman A. Grogin, Rachel Honor, Jake Summers, Nor Pirzkal, Aaron Robotham, Russell E. Ryan, Brent M. Smith, Haojing Yan, Cheng Cheng, Liam Nolan, Heidi B. Hammel, Stefanie N. Milam

Theme match 3/5

Digest

Bowling et al. decompose 36 NIRCam-selected AGN candidates in the PEARLS North Ecliptic Pole Time Domain Field using JWST/NIRCam plus HST imaging, then fit the point-source-subtracted host galaxies to recover SFRs and stellar masses. The host galaxies separate into two SFMS-offset populations: a bridge spanning the moderate-SFR radio sources down toward the low-SFR X-ray sources, and a distinct branch above ΔSFMS = -1 whose SFR rises with AGN fraction. The branch systems are mostly late-type galaxies with stronger nuclear point sources and frequent X-ray or radio counterparts, while the bridge systems are predominantly early types with weaker central components that may sometimes be compact bulges rather than secure AGN. Because both groups look transitional between star-forming and quiescent states yet do not split strongly by stellar mass or redshift, the paper argues that AGN activity is more closely tied to host star-formation state than mass alone.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 4. Use this figure to show the host-galaxy SED modeling that underlies the paper’s main measurements. It makes clear that the reported SFRs and stellar masses come from point-source-subtracted host emission across the HST and JWST bands, which is essential for trusting the later SFMS-offset analysis as a host-galaxy result rather than AGN-contaminated photometry.
Figure 5. This is the best comparison figure for placing the NIRCam-selected sample against the radio- and X-ray-selected AGN samples. The two panels and their histograms show how the PEARLS objects populate SFMS offset, sSFR, stellar mass, and AGN fraction space, making visible the bridge between the radio and X-ray populations and the fact that stellar mass is not the main separator.
Figure 6. This is the paper’s clearest single statement of the two-population result. It isolates the NIRCam-selected sample and shows the bridge and branch in SFMS offset versus AGN fraction, including the positive trend for the branch and the fact that 22 of 36 objects lie there, so it should be a headline figure for the digest.
Figure 7. Include this figure for the morphology-based interpretation of the two groups. The side-by-side F090W GALFIT models and residuals for branch and bridge examples let the reader see the late-type appearance of branch hosts and the more early-type character of bridge hosts after decomposition, which directly supports the physical distinction drawn in the text.
Figure 8. This synthesis figure is valuable because it tests which properties really separate the bridge and branch populations. The distributions show strong differences in SFMS offset, O24 AGN fraction, and F444W point-source fraction, while the stellar-mass distributions are much less distinct, matching the paper’s bottom-line claim that AGN-linked activity is more predictive than mass.

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2604.24892v1

Decoupling the AGN outflow and star-forming disk kinematics in the nuclear region of NGC 7582 with JWST NIRSpec and MIRI/MRS

Oscar Veenema, Niranjan Thatte, Dimitra Rigopoulou, Ismael García-Bernete, Almudena Alonso-Herrero, Miguel Pereira-Santaella, Anelise Audibert, Enrica Bellocchi, Andrew J. Bunker, Steph Campbell, Francoise Combes, Ric I. Davies, Fergus R. Donnan, Santiago García-Burillo, Omaira Gonzalez Martin, Laura Hermosa Muñoz, Erin K. S. Hicks, Sebastian F. Hoenig, Alvaro Labiano, Nancy A. Levenson, Chris Packham, Cristina Ramos Almeida, Claudio Ricci, Rogemar A. Riffel, David Rosario, Taro Shimizu, Lulu Zhang

Theme match 3/5

Digest

This paper uses JWST NIRSpec and MIRI/MRS integral-field spectroscopy from GATOS to map ionic lines spanning roughly 8-126 eV across the nucleus of the nearby Seyfert 2 NGC 7582, where a circumnuclear star-forming disk overlaps an AGN-driven bicone. Its main result is a clean kinematic stratification with ionisation potential: low-IP lines such as [Fe II], [Ar II], and [Ne II] follow disk rotation at PA about -12 degrees, while high-IP lines such as [O IV], [Mg IV], and [Ne V] align with the outflow at PA about 54 degrees and have broader profiles, with median dispersions of 119 +/- 13 km/s versus 78 +/- 11 km/s for the disk. For the mixed tracers [S III], [Ar III], and [Ne III], double-Gaussian fitting plus a thin-disk and 1D outflow model cleanly separates disk and cone contributions and shows that the outflow component is faster, broader, and lower-amplitude. The inferred hollow bicone can accelerate gas beyond the local escape velocity, and the nearly IP-independent cone opening angle argues that the torus polar region is largely unobscured rather than strongly stratified with photon energy.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1 is the orientation map for the whole paper because it identifies the circumnuclear disk or ring, the southern star-forming clumps, and the limb-brightened AGN bicone in lines with different ionisation potentials. It gives the reader the physical geography needed to understand why low-IP emission is associated with the disk while higher-IP emission increasingly follows the outflow.
Figure 5 is the clearest quantitative summary of the paper's headline result that kinematics separate by ionisation potential. The PA-versus-IP relation shows the transition from disk-dominated to outflow-dominated lines, and the right-hand panel is especially important because decomposing the intermediate-IP lines into disk and cone components resolves the ambiguous middle group into the same two kinematic families.
Figure 7 shows the actual double-Gaussian decomposition for the intermediate-IP lines, which is central because these are the lines where disk and outflow overlap most strongly. The recovery of distinct disk-like and cone-like velocity fields demonstrates that the mixed lines really do contain both components and that the separation is not just a fitting convenience.
Figure 10 connects the observed velocity maps to the paper's physical modeling by comparing the [Ne II] disk field and the [O IV] outflow field to best-fit thin-disk and 1D outflow models, with residuals smaller than the instrumental resolution. This is the key figure for understanding why the authors trust the model-assisted decomposition of the intermediate-IP lines and why they conclude that the outflow geometry is consistent with a hollow bicone.
Figure 13 carries one of the paper's broader physical conclusions by showing that the cone opening angle does not vary systematically with ionisation potential across the high-IP lines, including comparison to [O III]. That makes it the most important evidence for the interpretation that the torus polar region is largely unobscured and not strongly stratified in obscuring material as a function of photon energy.

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2604.26743v1

A Rare Eddington-Limited, Heavily Obscured Low-Mass Active Galactic Nucleus Likely Triggered by a Galaxy Merger

Shouyi Wang, Fan Zou, Chang-Hao Chen, W. N. Brandt, Elena Gallo, Bin Luo, Xue-Bing Wu, Yuming Fu, Dieu D. Nguyen, Shengxiu Sun

Theme match 2/5

Digest

This paper presents a multiwavelength case study of GAMA 376183, a low-mass-galaxy AGN first flagged by its unusually strong [Ne v] λ3426 emission and then followed up with ~100 ks of NuSTAR data. The hard-X-ray modeling confirms heavy obscuration with log N_H = 23.3^{+0.4}_{-1.2} and an intrinsic 2–10 keV luminosity of log L_X,int = 42.92^{+0.24}_{-0.20}, while the inferred Eddington ratio of about 0.8 points to rapid black-hole growth. High-resolution imaging shows a disturbed, likely merging system, and the UV-to-far-IR SED indicates a recent starburst, together supporting a picture in which the merger is driving both the buried accretion and host-galaxy activity. The broader significance is that GAMA 376183 is a rare heavily obscured AGN in a low-mass galaxy, and it highlights [Ne v] as a practical way to uncover this otherwise elusive population.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1. Use this figure to introduce why GAMA 376183 was selected in the first place. The paired GAMA and DESI spectra establish the unusually strong [Ne v] emission, show that the line is real in independent spectroscopy, and make clear that the source does not show obvious optical spectral variability between the two epochs.
Figure 3. This is the key morphology figure for the merger interpretation. The multiband HSC decomposition and residual maps reveal the disturbed host structure and the subcomponents labeled C1, C2, and C3, which is the direct imaging evidence behind the paper’s claim that the AGN likely resides in an ongoing merger.
Figure 4. Include this figure for the host-galaxy side of the coevolution argument. The UV-to-far-IR SED decomposition shows both the AGN contribution and the recent starburst component, connecting the buried accretion to contemporaneous host-galaxy growth rather than treating the X-ray result in isolation.
Figure 5. This is the central evidence figure for the obscured-AGN claim. The NuSTAR spectrum, especially the positive source signal above 10 keV and the BORUS fit, is what allows the authors to infer heavy obscuration and recover the intrinsic X-ray luminosity that places the source among the rare obscured AGNs in low-mass galaxies.
Figure 6. Use this as the synthesis figure that ties the paper together. By comparing the intrinsic 2–10 keV luminosity to [Ne v] and mid-infrared AGN luminosity indicators, it shows how strongly the observed X-ray output is suppressed by obscuration and reinforces the paper’s methodological point that [Ne v] can help find heavily obscured low-mass AGNs.