Concept and science of HiCIAO: high contrast instrument for the Subaru next generation adaptive optics

Abstract

Direct exploration of exoplanets is one of the most exciting topics in astronomy. Our current efforts in this field are concentrated on the Subaru 8.2m telescope at Mauna Kea, Hawaii. Making use of the good observing site and the excellent image quality, the infrared coronagraph CIAO (Coronagraphic Imager with Adaptive Optics) has been used for various kinds of surveys, which is the first dedicated cold coronagraph on the 8-10m class telescopes. However, its contrast is limited by the low-order adaptive optics and a limited suppression of the halo speckle noise.HiCIAO is a new high-contrast instrument for the Subaru telescope. HiCIAO will be used in conjunction with the new adaptive optics system (188 actuators and/or its laser guide star -AO188/LGSAO188) at the Subaru infrared Nasmyth platform. It is designed as a flexible camera comprising several modules that can be configured into different modes of operation. The main modules are the AO module with its future extreme AO capability, the warm coronagraph module, and the cold infrared camera module. HiCIAO can combine coronagraphic techniques with either polarization or spectral simultaneous differential imaging modes. The basic concept of such differential imaging is to split up the image into two or more images, and then use either different planes of polarization or different spectral filter band-passes to produce a signal that distinguishes faint objects near a bright central object from scattered halo or residual speckles.In this contribution, we will outline the HiCIAO instrument, its science, and performance simulations. The optical and mechanical details are described by Hodapp et al. (2006) 1 . We also present a roadmap of Japanese facilities and future plans, including ASTRO-F (AKARI), SPICA, and JTPF, for extrasolar planet explorations.

Vector vortex coronagraph: first results in the visible

“…16 The one-layer design, equipped with the central occulting spot, is sufficiently achromatic for direct implementation on the telescope for direct contrast improvements. As a matter of fact, a vectorial vortex has just been tested successfully on sky on the Palomar 5-meter Hale telescope.…”

High-Contrast Near-Infrared Imaging Polarimetry of the Protoplanetary Disk Around Ry Tau

“…Using coronagraphy, the ongoing survey "Strategic Explorations of Exoplanets and Disks with Subaru" (SEEDS; Tamura 2009) with Subaru/HiCIAO (Tamura et al 2006) and AO188 (Hayano et al 2004) has recently discovered structures in a number of protoplanetary disks (Thalmann et al 2010), in particular in the polarized intensity (hereafter PI) distribution in the near-infrared (Hashimoto et al 2011Muto et al 2012;Kusakabe et al 2012;Tanii et al 2012;Mayama et al 2012;Dong et al 2012a;Grady et al 2013;Follette et al 2013). PI imaging has been used for observations of most of the disks in the SEEDS program, since this suffers significantly less contamination from the stellar flux than the normal intensity I.…”

Taking the vector vortex coronagraph to the next level for ground- and space-based exoplanet imaging instruments: review of technology developments in the USA, Japan, and Europe

“…33 The case of GPI 34 is slightly more difficult since the technical choice favored by this facility is a reflective design for the coronagraph, while each one of the technologies presented here are for transmissive coronagraphs.…”