AGN torus detectability at sub-millimeter wavelengths: What to expect from ALMA continuum data

Abstract

We study the detectability of the emission associated with the AGN dusty structure at sub-mm wavelengths using ALMA, in a theoretical and observational way. Theoretically, we use the Clumpy models from Nenkova et al. together with the mid-infrared to X-ray and the radio fundamental plane scaling relations. We find that it is more likely to detect bigger and denser dusty tori at the highest ALMA frequency (666 GHz/450 micron). We also find that with 1h at 353 GHz/850 micron and 10h at 666 GHz/450 micron we can detect, with a high detection limit, a 1 mJy torus (characteristic of bright AGN). This means, an object for which the unresolved SED at 12 micron has a flux ~1mJy. Observationally, we use four prototypical AGN: NGC\,1052 (low-luminosity AGN), NGC\,1068 (Type-2), NGC\,3516 (Type 1.5), and IZw1 (QSO), with radio, sub-millimeter, and mid-IR data available. All the mid-infrared spectra are best fit with the smooth model reported by Fritz et al. A power law and a single, or a composition of, synchrotron component/s reproduce the cm radio wavelengths. We combined and extrapolated both fits to compare the extrapolation of both torus and jet contributors at sub-mm wavelengths with data at these wavelengths. Our observational results are consistent with our theoretical results. The most promising candidate to detect the torus is the QSO IZw1 (therefore, highly accreting sources in general), although it cannot be resolved due to the distance of this source. We suggest that to explore the detection of a torus at sub-mm wavelengths, it is necessary to perform an SED analysis including radio data, with particular attention to the angular resolution.

Accepted for publication in ApJ

References in corpus (21)

• AGN Dusty Tori: I. Handling of Clumpy Media
• Radiative Transfer Modeling of Three-Dimensional Clumpy AGN Tori and its Application to NGC 1068
• The Infrared Nuclear Emission of Seyfert Galaxies on Parsec Scales: Testing the Clumpy Torus models
• High-Velocity Bipolar Molecular Emission from an AGN Torus
• Parsec-scale dust distributions in Seyfert galaxies - Results of the MIDI AGN snapshot survey
• Nuclear 11.3$\mu$m PAH emission in local active galactic nuclei
• Radio Variability in Seyfert Nuclei
• Extended silicate dust emission in PG QSOs
• MOJAVE: Monitoring of Jets in AGN with VLBA Experiments. III. Deep VLA Images at 1.4 GHz
• ALMA HCN and HCO+ J=3-2 observations of optical Seyfert and luminous infrared galaxies -- Confirmation of elevated HCN-to-HCO+ flux ratios in AGNs --
• The Fundamental Plane of Black Hole Activity in the Optical Band
• Gemini Imaging of Mid-IR Emission from the Nuclear Region of Centaurus A
• Infrared spectra and photometry of complete samples of PG and 2MASS quasars
• On the LINER nuclear obscuration, Compton-thickness and the existence of the dusty torus; Clues from Spitzer/IRS spectra
• ALMA imaging of C2H emission in the disk of NGC1068
• A comparison of hard X-ray photon indices and iron \ka emission lines in X-ray luminous narrow- and broad-line Seyfert 1 galaxies
• X-ray spectral variability of LINERs selected from the Palomar sample
• The dusty tori of nearby QSOs as constrained by high-resolution mid-IR observations
• Investigating the dusty torus of Seyfert galaxies using SOFIA/FORCAST photometry
• On the disappearance of a cold molecular torus around the low-luminosity active galactic nucleus of NGC 1097
• A detailed analysis of the high resolution X-ray spectra of NGC 3516: Variability of the ionized absorbers

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• Physical parameters of the torus for the type 2 Seyfert IC 5063 from mid-IR and X-ray simultaneous spectral fitting