The Infrared Doppler (IRD) instrument is a fiber-fed high-resolution NIR spectrometer for the Subaru telescope covering the Y,J,H-bands simultaneously with a maximum spectral resolution of 70,000. The main purpose of IRD is a search for Earth-mass planets around nearby M-dwarfs by precise radial velocity measurements, as well as a spectroscopic characterization of exoplanet atmospheres. We report the current status of the instrument, which is undergoing commissioning at the Subaru Telescope, and the first light observation successfully done in August 2017. The general description of the instrument will be given including spectrometer optics, fiber injection system, cryogenic system, scrambler, and laser frequency comb. A large strategic survey mainly focused on late-type M-dwarfs is planned to start from 2019.
We report the current status of the Infrared Doppler (IRD) instrument for the Subaru telescope, which aims at detecting
Earth-like planets around nearby M darwfs via the radial velocity (RV) measurements. IRD is a fiber-fed, near infrared
spectrometer which enables us to obtain high-resolution spectrum (R~70000) from 0.97 to 1.75 μm. We have been
developing new technologies to achieve 1m/s RV measurement precision, including an original laser frequency comb as
an extremely stable wavelength standard in the near infrared. To achieve ultimate thermal stability, very low thermal
expansion ceramic is used for most of the optical components including the optical bench.
M. Tamura, H. Suto, J. Nishikawa, T. Kotani, B. Sato, W. Aoki, T. Usuda, T. Kurokawa, K. Kashiwagi, S. Nishiyama, Y. Ikeda, D. Hall, K. Hodapp, J. Hashimoto, J. Morino, S. Inoue, Y. Mizuno, Y. Washizaki, Y. Tanaka, S. Suzuki, J. Kwon, T. Suenaga, D. Oh, N. Narita, E. Kokubo, Y. Hayano, H. Izumiura, E. Kambe, T. Kudo, N. Kusakabe, M. Ikoma, Ya. Hori, M. Omiya, H. Genda, A. Fukui, Y. Fujii, O. Guyon, H. Harakawa, M. Hayashi, M. Hidai, T. Hirano, M. Kuzuhara, M. Machida, T. Matsuo, T. Nagata, H. Ohnuki, M. Ogihara, S. Oshino, R. Suzuki, H. Takami, N. Takato, Y. Takahashi, C. Tachinami, H. Terada
IRD is the near-infrared high-precision radial velocity instrument for the Subaru 8.2-m telescope. It is a relatively compact (~1m size) spectrometer with a new echelle-grating and Volume-Phase Holographic gratings covering 1-2 micron wavelengths combined with an original frequency comb using optical pulse synthesizer. The spectrometer will employ a 4096x4096-pixel HgCdTe array under testing at IfA, University of Hawaii. Both the telescope/Adaptive Optics and comb beams are fed to the spectrometer via optical fibers, while the instrument is placed at the Nasmyth platform of the Subaru telescope. Expected accuracy of the Doppler-shifted velocity measurements is about 1 m s-1. Helped with the large collecting area and high image quality of the Subaru telescope, IRD can conduct systematic radial velocity surveys of nearby middle-to-late M stars aiming for down to one Earth-mass planet. Systematic observational and theoretical studies of M stars and their planets for the IRD science are also ongoing. We will report the design and preliminary development progresses of the whole and each component of IRD.
HiCIAO is a near-infrared, high contrast instrument which is specifically designed for searches and studies for
extrasolar planets and proto-planetary/debris disks on the Subaru 8.2 m telescope. A coronagraph technique
and three differential observing modes, i.e., a dual-beam simultaneous polarimetric differential imaging mode,
quad-beam simultaneous spectral differential imaging mode, and angular differential imaging mode, are used
to extract faint objects from the sea of speckle around bright stars. We describe the instrument performances
verified in the laboratory and during the commissioning period. Readout noise with a correlated double sampling
method is 15 e- using the Sidecar ASIC controller with the HAWAII-2RG detector array, and it is as low as 5 e-
with a multiple sampling method. Strehl ratio obtained by HiCIAO on the sky combined with the 188-actuator
adaptive optics system (AO188) is 0.4 and 0.7 in the H and K-band, respectively, with natural guide stars that
have R ~ 5 and under median seeing conditions. Image distortion is correctable to 7 milli-arcsec level using
the ACS data as a reference image. Examples of contrast performances in the observing modes are presented
from data obtained during the commissioning period. An observation for HR 8799 in the angular differential
imaging mode shows a clear detection of three known planets, demonstrating the high contrast capability of
AO188+HiCIAO.
The High-Contrast Coronographic Imager for Adaptive Optics (HiCIAO), is a coronographic simultaneous differential
imager for the new 188-actuator AO system at the Subaru Telescope Nasmyth focus. It is designed primarily to search
for faint companions, brown dwarves and young giant planets around nearby stars, but will also allow observations of
disks around young stars and of emission line regions near other bright central sources. HiCIAO will work in
conjunction with the new Subaru Telescope 188-actuator adaptive optics system. It is designed as a flexible,
experimental instrument that will grow from the initial, simple coronographic system into more complex, innovative
optics as these technologies become available. The main component of HiCIAO is an infrared camera optimized for
spectral simultaneous differential imaging that uses a Teledyne 2.5 μm HAWAII-2RG detector array operated by a
Sidecar ASIC. This paper reports on the assembly, testing, and "first light" observations at the Subaru Telescope.
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.
Amplitude apodization of a telescope's pupil can be used to reduce the diffraction rings (Airy rings) in the PSF to allow high contrast imaging. Rather than achieving this apodization by selectively removing light at the edges of the pupil, we propose to produce the desired apodized pupil by redistributing the pupil's light. This lossless apodization concept can yield a high contrast PSF which allows the efficient detection of Earth-sized planets around stars at ~10pc with a 2m visible telescope in space. We review the current status of a JPL-funded study of this concept for the Terrestrial Planet Finder (TPF) mission, including a lab experiment and extensive computer simulations.
We introduce a near-infrared camera named coronagraph imager with adaptive optics (CIAO) mounted on the Subaru 8m telescope. Combined with the Subaru 36 elements adaptive optics (AO), CIAO can produce nearly diffraction limited image with approximately 0.07 arcsec FWHM at K band and high dynamic range imaging with approximately 10 mag difference at 1 arcsec separation under typical seeing conditions. We have carried out performance tests of imaging without and with coronagraph mask since its first light observation held on 2000 February. Because of limited weather conditions, the performance under best seeing conditions has not been tested yet. At a typical natural seeing condition of 0.4 - 0.8 arcsec, halo component of PSF using 0.2 - 0.8 arcsec mask can be reduced up to 70% comparing with that without mask using AO. Even after correction, residual wave front error has typically 1.2 rad2 which corresponds to the Strehl ratio of approximately 0.3 at K band. Such wave front errors degrades the image quality; this is a common problem of coronagraph on the ground-based telescope with non high-order AO. Nevertheless we emphasize that there are various advantages on our coronagraph: the clean PSF of CIAO, reduction of readout noise, and less effect of detector memory problem. Compared with coronagraphs on smaller telescopes, the PSF shape is sharper and it brings higher detectability of sources around bright objects.
We have carried out KHL band high resolution imaging and H band imaging-polarimetry of the Red Rectangle nebula using CIAO and 36 element AO mounted on the 8.2m Subaru telescope. HK band images show a X-shape structure close to 0.1 inch and 2 lobes with separation of 0.15 inch at the north and the south. Our L band image show a small clump and its position is 0.1 arcsec east from the center of the southern lobe. The polarization map shows roughly centrosymmetric vector pattern and the center of the pattern is consistent with that of 2 lobes. There is scatter of the vector pattern at approximately 0.1 inch east from the southern lobe and a local minimum in the degree of polarization. These results can explain that the primary star HD44179 is at 0.1 inch east from the southern lobes and the dominant illumination source is a M type star at the center of the nebula.
We report the development and performance of a near-IR polarimeter for the Subaru 8.2m telescope. The polarimeter is currently used with one of the Subaru instruments, CIAO, the stellar coronagraphic imager with adaptive optics. CIAO is the instrument specialized to obtain high contrast images of faint objects in the vicinity of bright objects. For achieving both high spatial resolution and high dynamic range, the instrument is used wiht the Subaru adaptive optics and has a dedicated cold coronagraphic capability. The polarimeter comprises two components. One component consists of an achromatic half-waveplate, an achromatic quarter-waveplate, and a calibration wire grid. Both half- and quarter-waveplates are rotatable and retractable, while the calibrator is only retractable. This componetn is placed upstream of any opticla components including adaptive optics system, which minimizes the effect of various mirros on instrumental polarization. The other component consists of two anlayzers, a cold wire grid and acold Wollastron prism. These are placed in the filter wheels of CIAO cryostat and can be chosen. The whole system is remotely controlled.
We describe a near-IR coronagraphic camera built for use with the Subaru 8.2-m telescope and its adaptive optics system. The purpose of this instrument CIAO is to obtain high-resolution images of faint objects in close vicinity of bright objects at IR wavelengths. Such a desire is strong in astronomy, especially in the study of companion brown dwarfs and extra-solar planets, circumstellar disks around both young stellar objects and main-sequence stars, jets and outflows form both young stellar objects and main-sequence stars, jets and outflows from both young stars and evolved stars, circumnuclear regions around AGNs, and host galaxies of QSOs. CIAO is a 1-5 micron camera with tow focal plate scales: 22 milli-arcsec/pixel and 11 milli-arcsec/pixel. The camera is equipped with the standard broad-band filters as well as a number of narrow-band filters. Choice of masks, filters and camera lenses and optical alignment with collimator and detector are made with cryogenic motors. CIAO utilizes one ALLADIN II 'science'-grade detector array manufactured by SBRC. Occulting masks whose diameter ranges from 0.1 to 3 arcsec and several types of pupil masks are selectable, all cooled down to about 60 K and the detector is cooled to about 30 K. Also available are a R <EQ 1000 grism with coronagraphic slits and a polarimetric module. We also present preliminary results from the first commissioning run at the Subaru telescope.
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