  Polarimetric study in the UV and optical has been one of the keys to reveal
the structure and nature of active galactic nuclei (AGN). Combined with the
HST's high spatial resolution, it has directly confirmed the predicted
scattering geometry of ~100 pc scale and accurately located the hidden nuclear
position in some nearby active galaxies. Recently, we are using optical
spectropolarimetry to reveal the nature of the accretion flow in the central
engine of quasars. This is to use polarized light to de-contaminate the
spectrum and investigate the Balmer edge spectral feature, which is otherwise
buried under the strong emission from the outer region surrounding the central
engine.

Astrophysics