Oral Presentation

How torus structure affects detection of polarized broad emission lines in active galactic nuclei

Kohei Ichikawa (Kyoto University) et al.

We present results from fitting the infrared spectral energy distributions of 21 active galactic nuclei (AGN). Combining the high spatial resolution infrared observations and clumpy torus models enables us to put tight constraints on the torus properties and geometry. We divide the sample into three types according to the broad line region (BLR) properties; type-1s, type-2s with scattered or hidden broad line region (HBLR) previously observed, and type-2s without any published HBLR signature (NHBLR). Comparing the torus parameters among three types, we find that NHBLR AGN have smaller torus opening angle, larger number of torus clumps, and larger covering factor than those of HBLR AGN. This suggests that the chance to observe scattered (polarized) flux from the BLR in NHBLR could be reduced by the dual effects of (a) less scattering medium due to the reduced scattering volume with small torus opening angle and (b) increased torus obscuration between the observer and the scattering region.