Spectroscopic study of NGC 1068 in the 3 mu m band

The results of a near-infrared (2.9-4.1 mu m) spectroscopic observation of NGC 1068 is presented. We detected an absorption feature near to 3.4 mu m caused by an obscuring torus as well as a broad (FWHM similar to 300 km s(-1)) Pf gamma emission line near to 3.75 mu m. The column density estimated from the 3.4 mu m feature corresponds to A(V) = 18-30 mag, which is far smaller than that inferred from hard X-ray observations. We conclude that the obscuring torus is highly concentrated to a thin disk, the thickness of which is less than 10(-1) pc, and that we view the obscuring torus from the exact edge-on direction. We have not detected the 3.3 mu m UIR (Unidentified InfraRed emission) feature in the central 3.'' 8 x 3.'' 8 region. This result implies that starburst activity just outside of the obscuring torus is absent.