Weekly issue

Week 19, 2026

May 4–10, 2026

Week 19, 2026 includes 7 curated papers, centered on spectroscopy, LRD, JWST AGN.

2605.04685v1

Compact, AGN-hosting Dwarf Galaxies with "Little Red Dots"-like SEDs in the Local Universe

Lulu Bao, Chao-Wei Tsai, Jingwen Wu, Jialai Wang

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Digest

Bao et al. compile a large local comparison set of 1,204 AGN-hosting dwarf galaxies, matched in broad luminosity regime to JWST little red dots, and classify them with K-means using rest-UV/optical SED shape plus galaxy size. The four resulting groups trace a sequence in UV-optical slope, metallicity, star formation, and dust emission, with roughly half of the local dwarf AGN sample showing the same kind of "V-shaped" SEDs and relatively compact morphologies that define LRDs. But the central result is negative in the most interesting way: the local V-shaped, compact systems are still systematically larger and show different ionization states than z>5 LRDs, implying they are more evolved systems rather than straightforward nearby counterparts. That matters because it argues against a simple local-analog picture and points instead to different black-hole/galaxy growth pathways across cosmic time.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 2 is the key comparison plot: inspect where the local ADGs fall in UV and optical continuum-slope space relative to the LRD density contours and the Kocevski et al. V-shaped selection window to see how much overlap is real versus superficial.
Figure 3a should show the paper's main phenomenology most clearly: compare the stacked SEDs of the four K-means groups to the LRD template to identify which groups truly reproduce the V-shaped UV-to-optical behavior and how the UV slope appears to drive the sequence.
Figure 3b is where the local-analog claim is tested morphologically: use the effective-radius distributions to see whether the V-shaped groups are genuinely compact and how their sizes still remain larger than the high-z LRD expectation.
Figure 4 helps connect the SED classes to dustier mid-IR behavior: inspect whether the groups with redder optical continua also move to distinct WISE color space, clarifying how AGN-heated dust emission differs across the sequence.
Figure 1 is worth checking for sample context before over-interpreting the analogy: the redshift distributions by selection channel show how heterogeneous the local ADG compilation is, including the systematically higher-redshift DESI broad-line subset.

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2605.07976v1

Testing the BH$^*$ Model: a UV-to-Optical Spectral Fitting of The Cliff

Rosa M. Mérida, Marcin Sawicki, Gaia Gaspar, Chris J. Willott, Kartheik G. Iyer

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Digest

Using the full JWST/NIRSpec PRISM spectrum of the z=3.55 little red dot The Cliff, this paper performs a self-consistent UV-to-optical Bagpipes fit with stellar, nebular, AGN, and blackbody components to test the BH* scenario. The fit naturally lands on a BH*-like solution: a ~5000 K reprocessing envelope accounts for the optical continuum, while the UV is consistent with a compact low-mass, star-forming, metal-poor host with non-negligible attenuation, with a fiducial log Mstar/Msun ~7.7 and A_V ~0.5. That matters because The Cliff was a key motivating object for the BH* picture, and here the model works even with broad priors while also extracting plausible host properties despite the source being unresolved in JWST imaging. The main remaining ambiguity is the UV mix: modest AGN leakage is allowed but not robustly required, and the inferred BH-to-stellar-mass ratio stays above standard BH-host scaling expectations.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Inspect the full PRISM spectrum with the component decomposition; this is the figure that shows whether one combined stellar+nebular+AGN+blackbody fit can really reproduce The Cliff's V-shaped UV-to-optical continuum in a self-consistent way.
Look for the continuum zoom around the Balmer-limit region and red optical slope; this should make clear why a ~5000 K blackbody-like envelope is favored for the optical light and why a purely stellar interpretation is disfavored for this source.
Check the posterior or model-comparison figure for the UV component; this is where to see why host-dominated UV and AGN+host UV solutions remain statistically equivalent, and how weakly the AGN leakage is actually constrained.
Inspect the dust-law sensitivity figure or table-equivalent plot; this is the place to learn how the inferred host properties shift from the fiducial solution to larger values, reaching roughly log Mstar/Msun ~8.1 and A_V ~1 depending on the attenuation law.
Look for the recovered star-formation history and BH-to-Mstar comparison panels; together they show the host's relatively smooth buildup, including assembly of ~10^7 Msun about 200 Myr before z=3.55, and the resulting tension with standard BH-host scaling relations.

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2605.05074v1

Little red dots as obscured little blue dots: relative abundances, luminosities, and black-hole masses

Piero Madau, Roberto Maiolino

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Madau and Maiolino test an orientation-based unification in which little red dots are simply dust-reddened, high-inclination versions of compact broad-line little blue dots drawn from the same z>4 BLAGN parent luminosity function. Their forward model combines super-Eddington anisotropic emission, an equatorially concentrated broad-line region, and clumpy circumnuclear dust, and it reproduces the observed UV LRD luminosity function over the JWST-constrained range. The inferred LRD fraction is strongly luminosity dependent, rising from about 3% at M_1500=-21 to a peak near 20% at M_1500=-19, with even larger apparent fractions predicted in the rest-frame optical, while the best fits favor per-cloud extinction around A_V≈2.8 and a modest mean dust covering factor of about 0.23. A notable consequence is that UV-selected LRDs should appear to host more massive black holes than unobscured LBDs, not because they are a separate population, but because dust preferentially removes lower-mass obscured systems from UV-selected samples.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Inspect Figure 1 first: it is the core demographic test, showing how the modeled LRD UV luminosity function sits below and steepens relative to the parent BLAGN LF, and how the apparent LRD/BLAGN fraction changes with observed M_1500.
Figure 2 is the key caveat figure because it visualizes the degeneracy between per-cloud extinction and mean dust covering factor; it shows that similar LRD counts can be produced by either stronger clouds with less covering or weaker clouds with more covering.
Figure 3 is the paper's payoff for black-hole demographics: compare the mass distributions of unobscured sightlines, all dust-intercepted systems, and the photometric LRD subset to see why UV-selected LRDs are biased toward higher inferred black-hole masses.
Within Figure 1, pay particular attention to the lower panel confidence band around the LRD fraction, since that directly encodes the paper's headline prediction that the obscured fraction is luminosity dependent rather than a simple geometric constant.
If the full paper includes any schematic of the thick-flow plus equatorial dust geometry, inspect it alongside Figures 1-2 to connect the phenomenology—anisotropic continuum, self-shadowing, and clumpy interception—to the fitted luminosity-function trends.

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2605.05301v1

An X-ray and optical spectral study of the changing-look narrow-line Seyfert 1 2MASX J0413-0050

A. Vietri, A. Tortosa, D. Ilić, S. Ciroi, M. Berton, E. Järvelä, C. Ricci, E. Sani, L. Crepaldi, B. Dalla Barba, S. Chen, E. Congiu, P. Condò, I. Varglund, G. Rodighiero

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Digest

This paper tracks the changing-look behavior of the narrow-line Seyfert 1 2MASX J0413-0050 across optical spectroscopy and X-ray observations spanning roughly 2004 to 2023. The key result is an unusual optical transition in 2021: the source moved toward a Seyfert 1.9 state with the complete disappearance of Hbeta even while remaining in a high-accretion regime, followed later by the re-emergence of both narrow and broad Hbeta in a Seyfert 1.8 phase. Over the same period, the X-ray flux declined from 2020 to 2022 and again in 2023, but the line-of-sight column density could not be constrained well enough to support a changing-obscuration explanation. The authors therefore argue that repeated switch-on/switch-off episodes in the accretion flow are the more plausible driver, making J0413-0050 a strong case that NLS1s can undergo genuine changing-state phenomena.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Inspect the multi-epoch optical spectra that cover Hbeta and Halpha to see the core changing-look evidence directly: the 2004 NLS1 classification, the 2021 disappearance of Hbeta, and the later re-emergence of broad and narrow Hbeta that shifts the source back to a Seyfert 1.8 state.
Look for any zoomed line-profile decomposition around the Balmer region, especially fits separating broad and narrow components plus Fe II if modeled; this should clarify whether the classification change is driven by genuine BLR fading rather than only continuum-placement or blending effects.
Find the X-ray spectral comparison across the 2020, 2022, and 2023 observations to check how the flux decline appears in practice and whether the spectra show strong absorption signatures, spectral-shape changes, or instead mainly luminosity evolution.
Prioritize any long-term timeline or summary figure combining optical type, Balmer-line visibility, and X-ray brightness versus observing date; that figure should be the fastest way to assess the proposed switch-on/switch-off history over the last two decades.
If present, inspect a diagnostic plot comparing accretion-state indicators with optical spectral type, since the paper’s most intriguing claim is that Hbeta vanished during a high-accretion phase rather than in an obvious low-state turn-off event.

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2605.03016v1

Resolving the Multiphase Outflow, Shock Signatures, and PAHs in the AGN-Starburst Composite ULIRG F10565+2448 with JWST MIRI/MRS

Kylie Yui Dan, Jerome Seebeck, Sylvain Veilleux, David Rupke, Eduardo Gonzalez-Alfonso, Ismael Garcia-Bernete, Weizhe Liu, Dieter Lutz, Marcio Melendez, Miguel Pereira Santaella, Eckhard Sturm, Francesco Tombesi

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Digest

JWST/MIRI MRS integral-field spectroscopy of the nearby ULIRG F10565+2448 isolates an unresolved nuclear outflow and a resolved kpc-scale warm-molecular outflow, allowing the authors to compare warm ionized gas, warm H2, and PAH-emitting material within the same merger-driven system. The nucleus shows a faster warm-ionized outflow with projected mean velocity up to -520 km/s, while the unresolved warm-molecular component is slower at -150 km/s; the resolved warm-molecular flow spans -280 to -110 km/s and is slightly hotter than the disk at 507 +/- 25 K versus 329 +/- 5 K. The spatially resolved H2 component also contains hotter, lower-column regions suggestive of a shock front, explored with the [Fe II] 5.34 um/Pf alpha diagnostic, while PAH ratios show a radial drop and then recovery in ionization and grain size from the center to 3 kpc. Altogether, the paper sharpens the case that F10565+2448 is a true AGN-starburst composite, with both black-hole and star-formation power needed to explain the outflow energetics, even though the warm-molecular phase likely does not escape the galaxy.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1 is worth checking first because the paper's kinematic claims depend on aggressive post-processing: it shows how the team combined pipeline 2D defringing with an extra spaxel-by-spaxel residual-fringe correction to recover cleaner MIRI/MRS line profiles across all four channels.
Figure 2 gives the nuclear spectral decomposition that underpins the rest of the analysis; inspect how the cool, warm, and hot dust continua, PAH templates, emission lines, and the 6.1 um water-ice absorption are separated, since that tells you how robust the derived PAH and line measurements are in this dusty ULIRG n…
Figure 3 appears to be the key nuclear outflow diagnostic: the trends of line velocity and width against ionization potential and critical density show whether the faster broad components are preferentially associated with higher-ionization gas, helping distinguish a compact AGN-driven ionized outflow from the broader…
Figure 4 is the cleanest line-profile evidence for the nuclear ionized outflow. Compare [Ne II], [Ne III], and [Ne V] directly to see the shared blueshifted broad component, the absence of a narrow [Ne V] core, and the phase stratification implied by the different neon ionization states; also note the nearby [Cl II] l…

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2605.02663v1

Jet-driven shocks and turbulence in radio-loud Active Galactic Nuclei observed with JWST MIRI/MRS

Rogemar A. Riffel, Gabriel L. Souza-Oliveira, Luis Colina, Almudena Alonso-Herrero, Marina Bianchin, Kalliopi M. Dasyra, Lorenzo Evangelista, Kameron Goold, Pierre Guillard, Rogério Riffel, Anil Seth, Thaisa Storchi-Bergmann, Nadia Zakamska, Samile Araujo-Santos, Anelise Audibert, Enrica Bellocchi, Steph Campbell, Françoise Combes, Guilherme S. Couto, José Henrique Costa-Souza, Richard I. Davies, Maitê S. Z. de Mellos, Tanio Díaz-Santos, Fergus R. Donnan, Ismael García-Bernete, Santiago García-Burillo, Laura Hermosa Muñoz, Erin K. S. Hicks, Alvaro Labiano, Enrique Lopez-Rodriguez, Vincenzo Mainieri, Christopher Packham, Miguel Pereira Santaella, Cristina Ramos Almeida, Claudio Ricci, Lucas Ramos Vieira, Vivian U

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Digest

This paper uses JWST/MIRI MRS maps of seven nearby radio-loud AGN—3C 293, 3C 305, Centaurus A, Cygnus A, IC 5063, NGC 1052, and M87—to test how radio jets affect both warm molecular and ionized gas on circumnuclear scales. The core result is that elevated H2/PAH ratios, higher H2 excitation temperatures, and shock-sensitive ionized-gas tracers ([Fe II], [Ne II], [Ne III]) all track enhanced turbulence, with the effect seen not only along the jet axis but also in regions perpendicular to it. That combination argues that jet-driven shocks dominate the excitation of the H2 rotational lines in most of the sample, rather than a purely radiative origin. For LRDigest readers, the interesting takeaway is that even in nearby systems the jet couples to the multiphase ISM more broadly than a narrow collimated channel, offering a resolved template for how mechanical feedback can restructure black-hole fueling environments.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1 is the scene-setter: inspect how the MIRI/MRS spaxel measurements populate the H2 S(3)/PAH 11.3 versus PAH plane relative to the Spitzer SF, BAT AGN, and radio-selected AGN comparison samples, which shows whether these radio-loud nuclei are genuinely H2-enhanced at resolved scales rather than only in integrat…
Figure 2 is the key diagnostic figure for the paper’s main claim. Compare the along-jet and perpendicular-to-jet spaxels in H2 S(3)/PAH versus H2 temperature, [Fe II]/PAH 11.3, and [Ne III]/[Ne II] to see whether shock-linked molecular excitation persists off-axis as well as within the radio channel.
Figure 3 is worth checking after Figure 2 because it compresses the source-by-source correlation behavior. Use it to identify which galaxies show statistically significant coupling between H2 excess, molecular heating, and shock tracers, and which systems break the pattern or only show it in one orientation.
Figure 4 is the best summary of the orientation test across the full sample. The paired along/perpendicular mean ratios, connected for each galaxy and color-coded by radio luminosity, let you judge whether the perpendicular enhancement is a subtle secondary effect or a systematic feature of powerful radio-loud AGN.
If the full paper includes the sample/property table near Section 2, inspect it alongside Figures 2–4 to connect each galaxy’s distance and radio power to its line-ratio behavior; that helps separate truly generic jet-ISM coupling from source-specific geometry.

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2605.07965v1

A Changing-Look Seyfert Discovered by eROSITA Reveals a Two-Component Broad-Line Region

Alex Markowitz, Mirko Krumpe, David Homan, Bożena Czerny, Mariusz Gromazdki, Hartmut Winkler, Joern Wilms, Steven Hämmerich, Georg Lamer, Tathagata Saha, David A. H. Buckley, Malte Schramm, Daniel E. Reichart, Mara Salvato, Pietro Baldini

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Digest

eROSITA caught HE 1237-2252 in a dramatic changing-look event, with the soft X-ray flux dropping by a factor of 17 in 18 months and a follow-up campaign tracking a roughly sevenfold rise in accretion rate relative to Eddington over the next 3 years. The source moved from Seyfert 1.0-1.2 in 2002 to 1.8 near the dip, then back to 1.0 within 3 months of recovery, while the broad Hbeta line flux changed by factors of 4-6. A key result is that the broad Balmer emission separates into two BLR components: a broad Gaussian from virialized gas at 27 +/- 3 light-days and a double-peaked diskline-like component arising beyond about 5 light-days, with the diskline contribution growing as the continuum brightens. Because the X-ray spectra show no strong obscuration and the IR continuum also dipped, the paper argues this was an intrinsic accretion pause, giving a rare view of how the BLR and corona reconfigure during a Seyfert changing-look cycle.

Open paper page arXiv abstract arXiv PDF Highlighted PDF

Key figures to inspect

Figure 1 is the place to verify the event chronology: it ties the eROSITA/XMM/Swift/NICER continuum changes to the optical, UV, IR, and broad Balmer light curves, letting you see the factor-17 soft-X-ray drop, the recovery phase, and how quickly the line emission responded.
Figure 2 should be inspected for the XMM spectral decomposition, especially to confirm the lack of strong obscuration and to see how the CompTT, hard power-law, and UxClumpy components divide up the X-ray continuum during the three XMM epochs.
Figure 3 is useful for understanding the broadband accretion-flow interpretation: the fitted optical/UV/X-ray SEDs show how the disk, coronal, host-galaxy, and torus components shift between states and support the claim of a changing intrinsic accretion rate rather than a simple line-of-sight absorption event.
Figure 4 gives the full sequence of 21 optical spectra, which is where the changing-look classification becomes visually obvious and where you can track the Balmer-profile evolution from a mainly broad Gaussian shape into a Gaussian plus increasingly prominent double-peaked structure.