Unveiling the nature of Seyfert nuclei with 1 - 100 micron spectral energy distributions

TL;DR

This study uses infrared spectral energy distributions and diagnostics to support the unified model of AGNs, suggesting that Seyfert 1 and 2 galaxies have similar central engines viewed at different angles, with evidence for a clumpy torus.

Contribution

It provides detailed modeling of 3-100 micron SEDs and mid-IR diagnostics for 87 Seyfert galaxies, advancing understanding of the dusty torus and starburst-AGN connection.

Findings

IR emission consistent with unified AGN model

Evidence for a clumpy torus structure

Correlation between star formation and AGN luminosity

Abstract

The infrared is a key wavelength regime for probing the dusty, obscured nuclear regions of active galaxies. We present results from an infrared study of 87 nearby Seyfert galaxies using the Spitzer Space Telescope and ground-based telescopes. Combining detailed modelling of the 3 - 100 micron spectral energy distributions with mid-IR spectral diagnostics and near-infrared observations, we find broad support for the unified model of AGNs. The IR emission of Seyfert 1s and 2s is consistent with their having the same type of central engine viewed at a different orientation. The nature of the putative torus is becoming clearer; in particular we present evidence that it is likely a clumpy medium. Mid-infrared correlations between tracers of star formation and AGN ionizing luminosity reveal the starburst-AGN connection implied by the black hole/bulge mass relation, however it is not yet clear if this is due to feedback.