Instruments
ULTIMATE-Subaru Project is the combined effort of (1) the development of the Ground-Layor Adaptive Optics (GLAO) for Subaru, and (2) the planning and development of the next-generation instruments that will work with the GLAO. The first part (GLAO development) of the project was officially accepted as the NAOJ's "A" project in 2019. The image below is the 3-D design of the Wavefront Adapter Flange (WAF) for the GLAO. The development of the WAF starts from the NsIR platform by 2025, and subsequentlly to Cs in coordination with the Phase II timeline (below). We are also intensely working on the Laser Guide Star system, the Adaptive Secondary Mirror for GLAO, and the related systems.
Instrument Plan
The second part of the project is the science instruments development. The GLAO for Subaru is expected to provide the median stellar FWHM of 0.2" to 0.3" over 14' FOV in K-band, which is the huge gain over the natural sky condition. We will prepare the instruments that can receive the benefit of GLAO to its maximum. We set three development phase (phase I -- III) for them.
Phase I Instrument -- MOIRCS and D-SHOOTER
The Phase 1 is the instrument for the GLAO performance verification. For the purpose, we will use MOIRCS by relocating it to the NsIR platform: visit the MOIRCS website for more detail about the detail of the instrument. Please note that the pixel scale of MOIRCS at NsIR platform will be changed to 0.105"/pix: the imaging field of view (FOV) will be 3'.6 × 6'.3, slightly smaller than the current size. The multi-object spectroscopy (MOS) function of MOIRCS will also be available, with the upgraded high-efficiency wide-band medium-resolution grisms. With the sharp image size provided by the GLAO, we will enjoy the highest-sensitivity MOS spectroscopic performance among existing 8-10m class telescopes.
We are also planning to make the instrument called D-SHOOTER, the spectrograph that can simultaneously take data from optical to NIR. To make the D-SHOOTER the most powerful instrument among the similar one in the world, we are also planning to make a further upgrade to the GLAO hardware for D-SHOOTER so that we can even apply the AO correction to the optical wavelength using the technique called Laser Tomographic Adaptive Optics (LTAO). The LTAO technical feasibility project is already on-going under the collaboration with Tohoku University in Japan (the ULTIMATE-START project).
Phase II Instrument -- WFI
The Wide-Field Imager (WFI) will be the main GLAO instrument which fully make use of the benefit of the GLAO. The instrument has 14' × 14' FOV with the pixel sampling of 0.1"/pix. A suite of the broad/medium/narrowband filters that are strategically designed will be available. The instrument will also allow the user filters. The WFI will be used as a workhorse instrument for a large imaging survey program.
The conceptual design study is intensely on-going. The image below is the current sketch of the WFI optics (copyrighted by ULTIMATE team).
Phase III Instrument -- Multi-IFU Instrument
As a final step of the instrument development, we are planning to have a powerful spectrograph which can pick up several targets from the wide FOV of the GLAO at Cs focus. A possible plan proposed is the fiber-fed deployable multi-Integral Field Uunit (IFU) system proposed by the Australian Astronomical Observatory. About 10 small IFUs, called STARBUG, will be moving around the surface of a glass plate on Cs to pick up targets. The light gathered by each STARBUG will be fed to the spectrograph via the high-throughput optical fibers. As there is no AO-corrected multi-IFU instrument in the world which can pick up targets across such a wide FOV of ULTIMATE-Subaru, it will be very powerful instrument for the spectroscopic survey of faint and relatively sparse objects such as clusters of young galaxies in the most distant universe.
The Phase III Instrument plan is still highly uncertain. We encourage YOU to propose your instrument for ULTIMATE-Subaru!!
Summary
Here is the summary of the preliminary instrument plan for ULTIMATE-Subaru.
Last Update: 2019-11-15