Thermal-infrared adaptive optics imaging- and spectro-polarimetry with the Infrared Camera and Spectrograph (IRCS) for the Subaru Telescope

Hiroshi Terada, Mitsuhiko Honda, Takashi Hattori, Tomoyuki Kudo, Jun Hashimoto, Makoto Watanabe

A thermal-infrared polarimetric capability of the Infrared Camera and Spectrograph (IRCS) for the Subaru Telescope is described. A new half-wave retarder for the thermal-infrared band in 2–5 µm is introduced into the Waveplate  Unit of the Nasmyth platform on the infrared side of the telescope to realize imaging- and     low resolution spectro-polarimetry in that wavelength region. Through day-time calibrations using a wire-grid polarizer, the peak efficiency of the polarization is found to be 90-98% consistently in both imaging- and spectro- polarimetry in the thermal-infrared bands. In 2016 May and 2017 June, two engineering observing runs have been carried out to verify the on-sky performance.

Proceedings of the SPIE

Society of Photo-Optical Instrumentation Engineers (SPIE)

10702

107022Y

10.1117/12.2313303