ReveaLLAGN 1: JWST Emission-Line Spectra Reveal Low-Luminosity AGN with UV-Deficient SEDs and Warm Molecular Gas

2026/01/23 by Kameron Goold, Anil Seth, Mallory Molina +20 · 1 voice
Physics and Astronomy · #astro-ph.GA

paper · pdf · doi:10.3847/1538-4357/ae4bdd

arxiv published 2026/01/23 · arxiv updated 2026/02/12

Abstract

We present near- and mid-infrared spectra of eight Low-Luminosity Active Galactic Nuclei (LLAGN), spanning nearly four orders of magnitude in black hole mass and Eddington ratio, obtained with JWST/NIRSpec and MIRI as part of the ReveaLLAGN program along with identical archival data of Cen A. The high spatial resolution of JWST cleanly separates AGN emission from host-galaxy contamination, enabling detections of high-ionization potential lines more than an order of magnitude fainter than previously measured. Emission-line diagnostics reveal a transition at log(L_bol/L_Edd) ~ -3.5, where the spectral energy distribution becomes increasingly deficient in ultraviolet photons. We find that rotational H₂ excitation temperatures are elevated (~500 K higher) compared to both higher-luminosity AGN and star-forming galaxies, while the H₂(0-0)S(3)/PAH_{11.3 μm} ratios are consistent with those observed in the AGN population. We discuss the possible roles of outflows, jets, and X-ray dominated regions in shaping the interstellar medium surrounding LLAGN. Silicate emission at ~10 μm, localized to the nuclear region, is detected in most ReveaLLAGN targets. This dataset offers the first comprehensive JWST-based characterization of infrared emission lines in the nuclear regions of LLAGN.

Citations

• WIggle Corrector Kit for NIRSpEc Data: WICKED
• Blowing star formation away in AGN Hosts (BAH) -- II. Investigating the origin of the H2 emission excess in nearby galaxies with JWST MIRI
• Systematic collapse of the accretion disc in AGN confirmed by UV photometry and broad line spectra
• Why are optical coronal lines faint in active galactic nuclei?
• Deconvolution of JWST/MIRI Images: Applications to an AGN Model and GATOS Observations of NGC 5728
• The 2023 release of Cloudy
• ReveaLLAGN 0: First Look at JWST MIRI data of Sombrero and NGC 1052
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package*
• The Infrared Database of Extragalactic Observables from Spitzer. -- II. The Database & The Diagnostic Power of Crystalline Silicate Features in Galaxy Spectra
• The Near-Infrared Spectrograph (NIRSpec) on theJames WebbSpace Telescope
• An Energetic Hot Wind from the Low-luminosity Active Galactic Nucleus M81*
• LeMMINGs – II. The e-MERLIN legacy survey of nearby galaxies. The deepest radio view of the Palomar sample on parsec scale
• Chandra Survey of Nearby Galaxies: an Extended Catalog
• State-of-the-art AGN SEDs for Photoionization Models: BLR Predictions Confront the Observations
• Universal bolometric corrections for AGN over 7 luminosity decades
• Active galactic nuclei winds as the origin of the H₂ emission excess in nearby galaxies
• The full infrared spectrum of molecular hydrogen
• A New Calibration of Star Formation Rate in Galaxies Based on Polycyclic Aromatic Hydrocarbon Emission
• An Improved Distance to NGC 4258 and its Implications for the Hubble Constant
• New evidence for the ubiquity of prominent polar dust emission in AGN on tens of parsec scales
• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole
• The Event Horizon General Relativistic Magnetohydrodynamic Code Comparison Project
• A Compact Jet at the Infrared Heart of the Prototypical Low-Luminosity AGN in NGC 1052
• Faraday rotation in the jet of M87 inside the Bondi radius: indication of winds from hot accretion flows confining the relativistic jet
• Mid-Infrared Spectroscopic Evidence for AGN Heating Warm Molecular Gas
• Measuring supermassive black hole peculiar motion using H₂O megamasers
• A New Technique for Measuring Polycyclic Aromatic Hydrocarbon Emission in Different Environments
• A lower limit to the accretion disc radius in the low-luminosity AGN NGC 1052 derived from high-angular resolution data
• Relativistic jet feedback III: feedback on gas disks
• LeMMINGs. I. The eMERLIN legacy survey of nearby galaxies. 1.5-GHz parsec-scale radio structures and cores
• Silicate Dust in Active Galactic Nuclei
• The Distance to M104
• Modelling the nebular emission from primeval to present-day star-forming galaxies
• Simulating galaxy formation with black hole driven thermal and kinetic feedback
• Far-infrared line spectra of active galaxies from the Herschel/PACS Spectrometer: the complete database
• Suppressing star formation in quiescent galaxies with supermassive black hole winds
• The 2 Ms Chandra Deep Field-North Survey and the 250 ks Extended Chandra Deep Field-South Survey: Improved Point-Source Catalogs
• The subarcsecond mid-infrared view of local active galactic nuclei: II. The mid-infrared--X-ray correlation
• The central parsecs of M87: jet emission and an elusive accretion disc
• The Mid-Infrared Instrument for theJames Webb Space Telescope, VI: The Medium Resolution Spectrometer
• Active galactic nuclei flicker: an observational estimate of the duration of black hole growth phases of ~1e5 years
• The Nuclear Near-Infrared Spectral Properties of Nearby Galaxies
• The central parsecs of active galactic nuclei: challenges to the torus
• The Coevolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe
• Hot Accretion Flows Around Black Holes
• Evolution of Broad-line Emission from Active Galactic Nuclei
• Spectral Models for Low-luminosity Active Galactic Nuclei in LINERs: The Role of Advection-dominated Accretion and Jets
• Dissecting X-ray-emitting Gas around the Center of our Galaxy
• Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies: Supplemental Material
• Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies
• The SED of Low-Luminosity AGNs at high-spatial resolution
• A combined Optical and X-ray Spectra Study for Type 1 AGN. III. Broadband SED Properties
• M94 As A Unique Testbed for Black Hole Mass Estimates and AGN Activity At Low Luminosities
• The Atlas3D project -- I. A volume-limited sample of 260 nearby early-type galaxies: science goals and selection criteria
• Spectral Energy Distributions of Weak Active Galactic Nuclei Associated With Low-Ionization Nuclear Emission Regions
• The spectral energy distribution of the central parsecs of the nearest AGN
• Towards a complete census of AGN in nearby Galaxies: a large population of optically unidentified AGN
• An X-ray view of 82 LINERs with Chandra and XMM-Newton data
• The mass of the black hole in Centaurus A from SINFONI AO-assisted integral-field observations of stellar kinematics
• AGN Dusty Tori: II. Observational Implications of Clumpiness
• On the Anomalous Silicate Emission Features of AGNs: A Possible Interpretation Based on Porous Dust
• Results from an Extensive Simultaneous Broadband Campaign on the Underluminous Active Nucleus M81*: Further Evidence for Mass‐scaling Accretion in Black Holes
• Nuclear Activity in Nearby Galaxies
• [Ne V] Emission in Optically Classified Starbursts
• Spitzer Uncovers Active Galactic Nuclei Missed by Optical Surveys in 7 Late-type Galaxies
• Piecing Together the X-ray Background: Bolometric Corrections for Active Galactic Nuclei
• Warm molecular hydrogen in the Spitzer SINGS galaxy sample
• Resolving the innermost parsec of Centaurus A at mid-infrared wavelengths
• The Discovery of an Active Galactic Nucleus in the Late-type Galaxy NGC 3621: Spitzer Spectroscopic Observations
• Dust Masses, PAH Abundances, and Starlight Intensities in the SINGS Galaxy Sample
• Low-luminosity active galactic nuclei: are they UV faint and radio loud?
• The distribution of silicate strength in Spitzer spectra of AGNs and ULIRGs
• The Mid-infrared Fine-structure Lines of Neon as an Indicator of Star For mation Rate in Galaxies
• The Mid-Infrared Spectrum of Star-Forming Galaxies: Global Properties of PAH Emission
• The AGN Obscuring Torus -- End of the "Doughnut" Paradigm?
• A Spitzer Infrared Spectrograph Survey of Warm Molecular Hydrogen in Ultra-luminous Infrared Galaxies
• Mid-infrared Spitzer spectra of X-ray selected Type 2 QSOs: QSO2s are not ULIRGs
• The Polycyclic Aromatic Hydrocarbon Emission Deficit in Low‐Metallicity Galaxies—ASpitzerView
• Mid Infrared Properties of Low Metallicity Blue Compact Dwarf Galaxies From Spitzer/IRS
• Pixie Dust: The Silicate Features in the Diffuse Interstellar Medium
• The many lives of active galactic nuclei: cooling flows, black holes and the luminosities and colours of galaxies
• Multiwavelength Monitoring of the Dwarf Seyfert 1 Galaxy NGC 4395. I. A Reverberation-Based Measurement of the Black Hole Mass
• Metallicity Effects on Mid-Infrared Colors and the 8 micron PAH Emission in Galaxies
• A Digital Archive of H i 21 Centimeter Line Spectra of Optically Targeted Galaxies
• Radio Sources in Low-Luminosity Active Galactic Nuclei.IV. Radio Luminosity Function, Importance of Jet Power, and Radio Properties of the Complete Palomar Sample
• Energy input from quasars regulates the growth and activity of black holes and their host galaxies
• Molecular Hydrogen and [FeII] in Active Galactic Nuclei
• Molecular Hydrogen and [Fe II] in Active Galactic Nuclei III: LINERS and Star Forming Galaxies
• PAHs as a tracer of star formation?
• A Catalog of Neighboring Galaxies
• The absence of crystalline silicates in the diffuse interstellar medium
• Warm dust and aromatic bands as quantitative probes of star-formation activity
• Local supermassive black holes, relics of active galactic nuclei and the X-ray background
• Resolved Mid-IR Emission in the Narrow Line Region of NGC 4151
• Mid-Infrared line diagnostics of Active Galaxies -- A spectroscopic AGN survey with ISO-SWS
• An ISO--SWS survey of molecular hydrogen in Starburst and Seyfert Galaxies
• On the Relationship Between Radio Emission and Black Hole Mass in Galactic Nuclei
• On the relation between the coronal line emission and the IR/X-ray emission in Seyfert galaxies
• The BL Lac heart of Centaurus A
• Nuclear Luminosities and Radio Loudness of Seyfert Nuclei
• Infrared Emission from Interstellar Dust. I. Stochastic Heating of Small Grains
• The SBF Survey of Galaxy Distances. IV. SBF Magnitudes, Colors, and Distances
• A grid of composite models for the simulation of the emission-line spectra from the NLR of active galaxies
• High Spatial Resolution Imaging of NGC 1068 in the Mid Infrared
• Spectral Models of Advection-Dominated Accretion Flows with Winds
• The supermassive black hole of M87 and the kinematics of its associated gaseous disk
• A Search for "Dwarf" Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies
• Advection-dominated Accretion: Underfed Black Holes and Neutron Stars

Discussions

• ReveaLLAGN 1 - JWST Emission-Line Spectra Reveal Low-Luminosity AGN with UV-Deficient SEDs and Warm Molecular Gas: arxiv.org/abs/2601.16977 -> James Webb Space Telescope uncovers secret supermassive b [bsky, 0 points, 0 comments]

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