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 spectra of two ultra-luminous Lyα emitters at z≈6.6 (COLA1, NEPLA4; not LRDs by color selection) reveal broad Balmer lines implying ~2×10^8 M⊙ black holes and extreme BH-to-stellar mass ratios of ~0.1–0.2, ≈400–800× the local relation. Stellar-population fits favor very young hosts (<50 Myr), inconsistent with the prolonged near-Eddington growth needed to reach these masses, pointing to earlier quasar episodes. The rare double-peaked Lyα profiles demand large, highly ionised bubbles and a locally boosted photoionisation rate, consistent with a recent quasar phase that shut down within <1 Myr. The systems are interpreted as post-quasar galaxies where AGN feedback delayed stellar assembly, offering an explanation for unexpectedly large ionised bubbles deep in reionisation.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Fig. 1: NIRSpec IFU Hβ+[O III] and Hα+[N II] complexes—inspect the broad Balmer components used for single-epoch virial MBH, the fitted narrow and outflowing components, and residuals that establish robust AGN line decompositions.
Fig. 2 (left): Black hole growth tracks versus assumed Eddington ratios—verify that matching the z≈6.6 MBH requires sustained near-Eddington growth and/or earlier episodes, underscoring an episodic duty cycle.
Fig. 2 (middle): BAGPIPES-derived stellar mass assembly—check that most of the stellar mass forms within the last <50 Myr, highlighting the recent starburst contrasted with earlier BH growth.
Fig. 2 (right): MBH/M* versus JWST AGN and z~6–7 quasars—see COLA1 and NEPLA4 at ~0.1–0.2 (≈400–800× local), bridging the gap between AGN hosts and faint quasars.
Lyα double-peaked profiles and IGM transmission modeling—use the blue peak and trough placement to infer a large ionised bubble and to read off the <1 Myr constraint on quasar shutdown.

Tags

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

First detection of spectroscopic variability in a z≈7 Little Red Dot (the GlimmIr): two deep JWST/NIRSpec F290LP/G395M epochs 99 days apart (~13 rest-days) show ~30% changes in the continuum and broad-line flux and a 42% drop in [O III]5008. Careful tests rule out slit placement and calibration systematics, and NIRSpec prism data (RUBIES ~1 year earlier; CAPERS within a rest-day of THRILS) reproduce similar continuum/[O III] differences. The fast [O III] response ties part of the narrow-line gas to the variable engine, implying direct sight-lines from the accretion disk beyond the BLR and covering fractions <100% for any high-density screen. Assuming an accreting BH origin, the result argues that [O III] is not galaxy-process dominated and black-hole property inferences must be rethought for LRDs.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1: Compare the two G395M/F290LP epochs (THRILS vs C3PO) in 2D/1D and the subtraction—verify ~30% continuum/broad-line changes and the pronounced [O III]5008 shift; use the per-element ratio panel and the CEERS-10444 MSA overlays to see why slit placement cannot explain the differences.
Figure 2: Inspect CAPERS vs RUBIES prism/clear spectra—confirm that continuum and [O III] differences persist in low‑resolution data taken ~1 year earlier and within a rest-day of THRILS, reinforcing true variability across modes and timescales.
Figure 3: Follow the synthetic F444W fluxes across all epochs and slit orientations—check that variability trends track across configurations, supporting that orientation/throughput is not the driver.
Figure 4: Look at brightest-nebular-line flux ratios for comparison sources—the GlimmIr stands out beyond the assumed 30% systematic band, strengthening the intrinsic-variability interpretation.

Tags

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

Using NIRCam+HST imaging of the NEP-TDF, the authors GALFIT-decompose 36 NIRCam-selected AGN candidates, subtract the nuclear PSF, and SED-fit host-only fluxes to place each galaxy relative to the SFMS. The hosts bifurcate into a bridge connecting radio-like moderate SFRs to the low-SFR X-ray locus (mostly early types with weak point sources) and a cleanly separated branch above ΔSFMS = −1 where SFR rises with AGN fraction (late types with X-ray/radio counterparts and stronger nuclei). Both groups show signs of recent movement between star-forming and quiescent states with no preference in stellar mass or redshift, implying current SFRs track AGN activity more than M*. A caveat is that some bridge “nuclei” may be compact stellar bulges rather than AGN.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1: Scan the redshift-ordered RGB cutouts to gauge the morphological split (early vs late types) and note X/R/X+R flags; this helps anticipate which objects populate the high-AGN-fraction branch versus the lower-SFR bridge.
Figure 2: Inspect GALFIT data–model–residual panels for IDs 2, 62, and 40 across filters to see how well the central PSF is isolated; strong residual cores flag truly nucleus-dominated systems, while smooth residuals suggest compact bulges that could mimic weak AGN (key to the bridge caveat).
Figure 3: For ID 27, compare point-source (gold) vs total (blue) magnitudes versus rest wavelength to identify where the nucleus dominates (NIRCam) and where the host takes over (UV/optical), validating the need for host-only SEDs in SFMS offsets.
Figure 4: Read off CIGALE host SED components and best-fit parameters (log SFR, M*, attenuation, dust) across the sample; use these to visualize which galaxies sit above the ΔSFMS = −1 threshold (branch) versus below (bridge).

Tags

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

JWST/NIRSpec and MIRI/MRS IFS map ionic lines spanning ~8–126 eV in NGC 7582’s nucleus, cleanly separating the rotating circumnuclear disk from an AGN-driven outflow. Single/double-Gaussian fitting shows low-IP ([Fe II], [Ar II], [Ne II]) lines track disk rotation at PA ≈ −12 ± 3°, while high-IP ([O IV], [Mg IV], [Ne V]) align with a bicone outflow at PA ≈ 54 ± 10°, with higher dispersions in the outflow (σ ≈ 119 ± 13 km/s) than in the disk (σ ≈ 78 ± 11 km/s). Intermediate-IP lines ([S III], [Ar III], [Ne III]) carry both components, and a thin inclined disk plus 1D outflow model robustly decouples and quantifies their velocity fields. The outflow is a hollow bicone capable of accelerating gas beyond the local escape speed, with an opening angle independent of IP, implying largely unobscured polar regions of the torus.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1: Use the [Ar II], [Ar III], and [Ne V] flux maps to outline the circumnuclear disk/ring, pinpoint SF1/SF2 star-forming clumps, and trace the limb-brightened ionisation cones; note the stronger, blueshifted western cone versus the receding eastern side, anchored to the AGN continuum peak.
Figure 2: Inspect velocity fields ordered by IP to verify the PA flip between disk rotation and outflow; low-IP maps show coherent rotation, while high-IP maps align with the bicone, quantifying the ≈−12° vs ≈54° axes and the stratified kinematics.
Figure 3: Compare continuum-subtracted flux distributions across IP to see low-IP emission concentrated in the star-forming ring and high-IP emission extending along the cones; intermediate-IP lines reveal spatial mixing of disk and outflow.
Figure 4: Examine velocity dispersion maps to confirm σ contrasts—low in the ring, elevated in the cones—supporting the double-Gaussian decomposition (outflow = higher σ, lower amplitude, higher centroid velocities).

Tags

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

GAMA 376183 is singled out by an exceptionally strong [Ne v] λ3426 line (rest‑frame EW ≈ 48 Å) in a low‑mass host (M* ≈ 10^10 M⊙), with consistent GAMA and DESI spectra across epochs. ~100 ks NuSTAR follow‑up confirms heavy obscuration (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}. Imaging and SED modeling reveal a disturbed, likely merging system with subcomponents (C1–C3) and a recent starburst, while the inferred Eddington ratio λ_Edd ≈ 0.8 signals rapid black‑hole growth. Together, these point to merger‑triggered, Eddington‑limited accretion in a rare low‑mass case and showcase [Ne v] as an efficient selector of heavily obscured low‑mass AGN.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1: Use the [Ne v] λ3426 zoom‑in and two‑Gaussian fit to verify the extreme EW and line width; compare GAMA vs DESI spectra to confirm the stated lack of variability across epochs.
Figure 2: Locate GAMA 376183 on the Kewley‑demarcated BPT plane to see that AGN ionization dominates over any starburst contribution implied by the SED.
Figure 3: Inspect the HSC multiband decomposition and residual maps to identify disturbed structure and the C1–C3 subcomponents; check how disk/bulge subtraction and the radial profile support a merger interpretation.
Figure 4: Examine the CIGALE SED decomposition to gauge AGN vs host contributions and the recent‑burst component; compare sfhdelayedbq vs sfhdelayed fits for burst age and IR energy balance.