GREX-PLUS (Galaxy Reionization EXplorer and PLanetary Universe Spectrometer) is one of the three candidates of ISAS/JAXA’s Strategic L-class mission for the 2030s. The 1.2 m aperture, 50 K cryogenic space telescope with the wide-field camera (WFC) will provide the 1,260 square arcmin field-of-view for five photometric bands between 2 and 8 μm. The high resolution spectrometer (HRS) will observe the 10–18 µm with a wavelength resolution of 30,000. The GREX-PLUS WFC field-of-view is 130 times larger than that of the James Webb Space Telescope and similar to those of Euclid and Roman Space Telescope. Since these two survey missions are limited to the wavelength less than around 2 µm, GREX-PLUS will extend the wavelength coverage beyond 2 μm, providing versatile legacy imaging survey significantly improved from previous Spitzer imaging survey in the same wavelength range. The spectral resolution of the GREX-PLUS HRS is 10 times higher than that of the James Webb Space Telescope, opening a new window of the mid-infrared high-resolution spectroscopy from space. The main scientific themes are the galaxy formation and evolution and the planetary system formation and evolution. The GREX-PLUS WFC aims to detect the first generation of “bright” galaxies at redshift z > 15. The GREX-PLUS HRS aims to resolve the Kepler motion of water vapor molecules and identify the location of the water “snowline” in ∼ 100 proto-planetary disks. Both instruments will provide unique data sets for a broad range of scientific topics including galaxy mass assembly, origin of super massive blackholes, infrared background radiation, molecular spectroscopy in the interstellar medium, transit spectroscopy for exoplanet atmosphere, planetary atmosphere in the Solar system, and so on. This paper presents the status of the concept design of GREX-PLUS, including telescope system, WFC, HRS, cooling system, and spacecraft bus system.
We propose a new high contrast imager for Kyoto 4m segmented telescope called SEICA (Second-generation
Exoplanet Imager with Coronagraphic Adaptive optics), aiming at detection and characterization of selfluminous
gas giants within 10AU around nearby stars. SEICA is aggressively optimized for high performance
at very small inner working angle, 10-6 detection contrast at 0".1 in 1-hour integration. We start the on-sky
commissioning test in 2016 and the science observations in 2017. Since it is the first time to realize the highcontrast
imaging on the segmented telescope, SEICA is an important step toward future high contrast
sciences on Extremely Large Telescopes (ELTs). This paper presents an overall of the SEICA program and
the conceptual design for ultimate performance under given atmospheric conditions.
Fiber Multi Object Spectrograph “FMOS” on Subaru Telescope is capable of configuring 400 fibers on the 30-
arcmin diameter field of view at the prime focus for near-infrared (0.9–1.8 μm) spectroscopy, and this instrument
has been open as a common-use instrument since May 2010. In this article, an overview of the instrument is
given first, and then the typical operational sequence in science observation and a few notable features of the
instrument are explained. In (see manuscript) 5, the instrument performance in terms of fiber positioning, auto guiding, and
sensitivity to emission lines are highlighted. Recently (since March 2012) a Subaru Strategic Program (SSP)
has started with FMOS to conduct a wide-field galaxy survey for a cosmological experiment. Upgrading fiber
configuration by using a “metrology camera” has also been under discussion, which will enable to measure the
positions of the 400 fibers quickly and shorten the fiber configuration time significantly. We will also report the
status of these recent activities.
A 3.8 m segmented telescope is planned to be built at the Okayama Astrophysical Observatory by the joint
program among Kyoto university, Nagoya university, NAOJ, and Nano-Optonics Energy Inc. This is the world’s
first optical-infrared telescope whose primary mirror is composed of “petal-shaped” segment mirrors.
To investigate the best layout of the displacement sensors as well as to study the control algorithm, we have
developed a simulation software for the segmented petaloid mirrors. This simulator calculates the vertical position
differences between the segments at the 60 displacement sensors based on the three-dimensional movements of
the 54 actuators, and enables us to test the control algorithms under various conditions including random noise
on the displacement sensors, random movement errors of the actuators, and unexpected lateral shifts of the
segments. The outputs of the simulator are not only the phase error of the primary mirror but also the PSF
image, taking the structure function of the optical surfaces into account.
Using a singular value decomposition method, we found that the 18 petal-shaped segments are controllable
within the required displacement errors of 15 nm under the following three conditions: 1) the displacement
measurement sensors are placed in staggered fashion between segments, 2) the displacement measurement sensors
are axisymmetrically placed with respect to the optical axis, and 3) the relative lateral shift and rotation of each
segment are less than 500 μm and 0.05 degree, respectively.
In this report, the control algorithm, requirements for the layout of the displacement measurement sensors,
and the simulated performance will be presented.
We are now prototyping an integral field unit (IFU) using micro-lenses
and optical fibers for a new integral field spectrograph (IFS). The IFS is one of the primary instruments of a new 3.8m telescope which is under development. We report a basic concept of the IFS and current status of the prototyping work. One of main objectives of the 3.8m telescope is prompt follow-up spectroscopy of rapidly variable astronomical objects such as gamma-ray bursts (GRBs). The IFS allows us to omit procedures of target identification and acquisition, and to start exposure very quickly. We are developing a prototype IFU for the IFS in order to establish the construction techniques. We have already finished basic design, and moved to detailed design phase. We will install the prototype IFU into an existing optical imaging spectrograph of the 188cm telescope at Okayama Astrophysical Observatory for test observations. Through the test observations, we will establish the observing procedures and the data reduction techniques. The prototype IFU has the 20 x 20 arcsec^2 field of view (FoV) and the 2 arcsec spatial sampling on the 188cm telescope. The new IFS will have the 20 x 20 arcsec^2 FoV and the 1 arcsec spatial sampling on the 3.8m telescope. The X-ray telescope of the Swift satellite distributes GRB locations with a typical accuracy of 3-5 arcsec after 70 sec from GRB triggers. The FoV of the new IFS is much wider than this localization error circle and allows us to make prompt spectroscopy of GRBs.
The Fibre Multi-Object Spectrograph for Subaru Telescope (FMOS) is a near-infrared instrument with 400
fibres in a 30' filed of view at F/2 prime focus. To observe 400 objects simultaneously, we have developed a fibre
positioner called "Echidna" using a tube piezo actuator. We have also developed two OH-airglow suppressed and
refrigerated spectrographs. Each spectrograph has two spectral resolution modes: the low-resolution mode and
the high-resolution mode. The low-resolution mode covers the complete wavelength range of 0.9 - 1.8 μm with
one exposure, while the high-resolution mode requires four exposures at different camera positions to cover the
full wavelength range. The first light was accomplished in May 2008. The science observations and the open-use
observations begin in May 2010.
Fibre Multi-Object Spectrograph (FMOS) is the next common-use instrument of Subaru Telescope. FMOS consists of
three subsystems; the Prime focus unit for Infrared (PIR), the fibre positioning system/connector units, and the two
infrared spectrographs. The PIR was transferred to the Subaru Observatory in the spring of 2005 to check the optical
performance on the telescope. As a result of the test observation, we found that the adjustment of the optical axis
between PIR and the primary mirror was difficult with the initial design of the corrector alignment stage. Furthermore,
the optical axis of the telescope moved over a little owing to an earthquake in Hawaii Island in Oct. 2006. Therefore we
decided to modify mechanical structure of PIR, the corrector alignment stage as well as the cable wrapping system. This
modification was completed in the summer of 2007. In this proceeding, we report the mechanical structure of the new
PIR and the results of the engineering observations.
FMOS: the Fiber Multiple-Object Spectrograph is the next common-use instrument of the Subaru Telescope,
having a capability of 400 targets multiplicity in the near-infrared 0.9-1.8μm wavelength range with a field
coverage of 30' diameter. FMOS consists of three units: 1) the prime focus unit including the corrector lenses,
the Echidna fiber positioner, and the instrument-bay to adjust the instrument focus and shift the axis of the
corrector lens system, 2) the fiber bundle unit equipping two fiber slits on one end and a fiber connector box with
the back-illumination mechanism on the other end on the bundle, 3) the two infrared spectrographs (IRS1 and
IRS2) to obtain 2×200 spectra simultaneously. After all the components were installed in the telescope at the
end of 2007, the total performance was checked through various tests and engineering observations. We report
the results of these tests and demonstrate the performance of FMOS.
Fibre Multi-Object Spectrograph (FMOS) is one of the second-generation instruments of Subaru Telescope. FMOS is consisted of a number of subsystems; the Prime focus unit for IR (called PIR), the fibre positioning system/connector units, and the two spectrographs. The PIR and one spectrograph were made in Kyoto University, and were brought to the Subaru telescope last spring. The PIR attached to the telescope and stellar images were obtained for optical alignment in July and October last year. We report on these engineering run in this proceeding.
The Fiber Multiple-Object Spectrograph for Subaru Telescope (FMOS) is quite large instrument composed of
the prime focus unit, the fiber bundle unit, and the two infrared spectrographs. Among these units, a part of the
prime focus unit and one of the spectrograph were transported from Kyoto University to the Subaru Observatory
in the middle of 2005. We present the optical and the mechanical components of the spectrograph, which was
reassembled on the new floor of the Subaru dome. We also show the preliminary results of the optical alignment
and the cooling test of the instrument at the summit of Mauna Kea.
The Fibre Multi-Object Spectrograph (FMOS) for the primary focus
of Subaru Telescope is one of the second generation
instruments, aiming at acquiring spectra of faint objects with
target multiplicity of up to 400. The optimised wavelengths span
from 0.9 to 1.8 microns so as to extend our knowledge of galaxy
formations and evolutions at higher redshifts in a systematic way,
as well as of variety of intriguing near-infrared objects.
On the basis of detailed design of FMOS, actual processes of
fabrication are in progress, and some of critical hardware
components have successfully been developed. In this report,
we present the status of the FMOS project, the results of
developed components, and also instrument control systems such
as the new detector electronics as well the related contol
softwares.
The Fibre Multi-Object Spectrograph (FMOS) is a second-generation common-use instrument of the Subaru telescope. Under an international collaboration scheme of Japan, UK, and Australia, a realistic design of FMOS has been already in completion, and the fabrications of hardware components have been in progress. We present the overall design details together with the special features of FMOS subsystems, such as the prime focus corrector, the prime focus mechanical unit including fiber positioners, and the near-infrared spectrograph, etc.
CISCO is an IR camera and spectrograph based on a single 1024 X 1024 HgCdTe array detector, which has been developed as a back-end spectrograph of OHS. It is also designed to be mounted on the Cassegrain or Nasmyth focus directly as an independent instrument. In addition to the normal imaging and spectroscopy modes, CISCO has a slitless prism spectroscopy mode at resolving power of approximately 30. This mode is primarily aimed at detecting the H(alpha) emission line of forming galaxy at z equals 2.05-2.65. The development of CISCO is in near completion, showing results of test observations carried out using a 1.5m telescope.
The infrared instrumentation plan for the Subaru telescope is described. Four approved infrared instruments and one test observation system are now in the construction phase. They are coronagraph imager using adaptive optics (CIAO), cooled mid- infrared camera and spectrograph (COMICS), infrared camera and spectrograph (IRCS), OH-airglow suppressor spectrograph (OHS) and mid-infrared test observation system (MIRTOS). Their performance goals and construction schedules are summarized. The plan for procurement and evaluation of infrared arrays required by these instruments is briefly described.
A specially designed faint object spectrograph in the near-IR region from 1 to 2 micrometers is proposed for the Japanese National Large Telescope: SUBARU. The proposed instrument called OHS for SUBARU is kind of a pre-optics system capable of eliminating most of intense OH airglow emission lines from the incident beam in the J- and H-passbands. The detectivity for objects in the faintest end is supposedly enhanced with this spectroscopic filter system by removing nearly 95% of the natural sky background: the non-thermal night airglow emission. The sensitivity gain in terms of limiting magnitude in these wavelength bands is expected to be 1 to 1.5 mag, depending on the modes of observations. The expected performance of the prototype OHS when attached to SUBARU will also be presented.
The design of an OH airglow suppressor spectrograph for use on the University of Hawaii 2.2 m telescope is presented. The unique feature of the pre-optics system for low resolution spectroscopy in the 1.1 to 1.8 micrometers range is the capability of removing most of the intense OH emission lines by a specially designed spectroscopic mask. With the OH suppressor spectrography, the background flux is reduced to about 1/30 the natural background on the average. The sensitivity gain in terms of limiting magnitude is expected to be approximately 1.5 mag, compared with the conventional method.
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