ReveaLLAGN 3: Revealing the Infrared Spectral Energy Distributions of Low Luminosity AGN
David Ohlson, Anil C Seth, Kameron Goold, Nischal Acharya, Torsten Böker, Antoine Dumont, Ruby Duncan, Michael Eracleous, Anja Feldmeier-Krause, Juan Antonio Fernández-Ontiveros, Elena Gallo, Andy D Goulding, Jenny E Greene, Luis C Ho, Sera B Markoff, Mallory Molina, Richard M Plotkin, Almudena Prieto, Shobita Satyapal, Glenn van de Ven, Jonelle L WalshAbstract
The spectral energy distributions of active galactic nuclei (AGN) provide valuable information on the emission mechanisms taking place in their inner regions. Here we use the James Webb Space Telescope to study the near and mid-infrared spectral energy distributions of seven nearby low-luminosity active galaxy nuclei from 1.7 to 24 μm. We cleanly separate the AGN spectrum by performing spatial fits of the two-dimensional images across all wavelengths. We then compare these clean unresolved spectra to aperture-based spectra and show that they effectively remove galaxy contamination. Comparing our infrared measurements to X-ray emission, we find that low-luminosity AGN have enhanced near-infrared emission relative to more luminous AGN, a trend that correlates with radio-loudness, while their mid-infrared-to-X-ray ratios are comparable. A majority of our targets show strong compact silicate emission suggesting the presence of warm dust on parsec scales in these systems. We also quantify the near- and mid-infrared power-law slopes and colors of low-luminosity AGN. In the near-infrared we find AGN of all luminosities have similar spectral slopes and colors, however in the mid-infrared, we find low-luminosity AGN typically have steeper slopes and redder colors than more luminous AGN. Both the strong silicate emission and steep mid-infrared slopes disagree with existing models for low-luminosity AGN spectral energy distributions.