CIAO: Coronagraphic Imager with Adaptive Optics on the Subaru Telescope

摘要

We present the performances of direct imaging with adaptive optics, coronagraph, and imaging-polarimetry of the coronagraphic imager with adaptive optics (CIAO) for the Subaru telescope. Combining with the 36-element adaptive optics system, CIAO produces high-resolution images with a full width at half maximum of 0."072 and a Strehl ratio of 0.28 in the K band. CIAO has a Lyot's-type stellar coronagraph facility with 0."1 to 4."0 diameter masks. The limiting magnitude difference of a companion star at the K band is 11.0mag at 5σ, 10 minutes integration time, and 2."0 separation from the central star. CIAO also has a polarimetry facility with a rotatable half-wave plate and a wire grid polarizer. Currently, the measurement of JHK band linear polarization is available.