A near-infrared polarized bipolar cone in the Circinus galaxy

We present near-infrared broad-band polarization images of the nuclear regi ons of the Circinus galaxy in the J, H and K bands. For the first time the south-eastern reflection cone is detected in polarized light, which is obsc ured at optical wavelengths behind the galactic disc, This biconical struct ure is clearly observed in J- and H-band polarized flux, whilst in the K ba nd a more compact structure is detected. Total flux J - K and H - K colour maps reveal a complex colour gradient toward the south-east direction (wher e the Circinus galactic disc is nearer to us). We find enhanced extinction in an are-shaped structure, at about 200 pc from the nucleus, probably part of the star formation ring. We model the polarized flux images with the scattering and torus model of Y oung et al., with the same basic input parameters as used by Alexander et a l. in the spectropolarimetry modelling of Circinus, The best fit to the pol arized flux is achieved with a tonus radius of similar to 16 pc, and a visu al extinction A(nu), through the torus, to the near-infrared emission regio ns of >66 mag.