Petite AGNs Reveal New Secrets

The strength of the silicate dust emission feature in many of the low-luminosity AGN (denoted S10, the black circles), is unusually large compared to the amount of gas in their nucleus (measured by log NH). One possible explanation is that these galaxies harbour just a small amount of optically-thin dust, which is expected according to some models that predict the disappearance of the dusty torus in low-luminosity AGN.