In "The Central Engine of Active Galactic Nuclei", ASP Conference Series, Vol. 373, Xi'an, China, 16-21 October, 2007, eds. L. C. Ho and J.-M. Wang

For a PDF version of the article, click here.

Abstract. Dust plays an essential role in the unification theory of active galactic nuclei (AGNs). This review summarizes our current understanding of the extinction and infrared emission properties of the circumnuclear dust in AGNs as well as the inferred dust composition and size distribution.

Table of Contents

• INTRODUCTION: ARE ALL AGNS BORN EQUAL? - THE ROLE OF DUST IN THE UNIFIED SCHEMES OF AGNs
• EXTINCTION - A POWERFUL DISCRIMINATOR OF DUST SIZE
• Interstellar Extinction: Milky Way, SMC, and LMC
• AGN Extinction - "Gray" or SMC-like Extinction?
• DUST SPECTROSCOPY - DIAGNOSIS OF DUST COMPOSITION
• The 2175 Å Extinction Bump
• The 3.4 µm Aliphatic Hydrocarbon Absorption Feature
• The 9.7 µm and 18 µm Silicate Absorption and Emission Features
• The 3.3, 6.2, 7.7, 8.6 and 11.3 µm PAH Emission Features
• The Ice Absorption Features
• IR EMISSION MODELING - INFERRING DUST SIZE AND TORUS GEOMETRY?
• REFERENCES