Status ofFMOS Development
Toshinori Maihara, Masahiko Kimura, Shigeru Eto, Fumihide Iwamuro and Koji Ohta
Department of Astronomy, School of Science, KyotoUniversity, Kitashirakawa, Kyoto, Japan
and
Masayuki Akiyama, Jun'ichi Noumaru, and Hiroshi Karoji
Subaru Telescope, O'haula, Hilo, Hawaii98622, USA
abstract
The FMOS project has been conducted under the international collaboration framework, which consists of Japan (Subaru Telescope and KyotoUniversity), Australia (Anglo-Australian Observatory), and United Kingdom (University of Oxford, University of Durham and Rutherford Appleton Laboratory). The actual construction of FMOS has been in progress at the respective institutes responsible for designing and fabricating subsystems based on the agreed overall FMOS specifications. Each process of fabrication has been undertaken in the Subaru contract scheme, which assumes a target date of delivery of each subsystem to Hawaii within the Japanese FY 2004 (the end of March, 2005).
1. Introduction
This is the first scientific meeting on international basis, since the FMOS project was started in 1999. Looking back briefly before 1999, we had had extensive discussion in the optical/infrared community in Japan, as well as in UK and Australia, about a multi-object, prime-focus spectrograph using optical fibres, and we had reached the present “instrument definition” of FMOS by the end of 1999.
The first period from FY1999 to FY2000 was devoted to preliminary design studies of optical system as a whole, from which we could get a basic and concrete concept of the present FMOS.Based on the revised FMOS concept, along with a very rough cost estimate, I submitted a proposal of FMOS as one of the second-generation instruments to “Subaru Advisory Committee”.
The Subaru Advisory Committee together with the “Instrument Review Committee” have reviewed the proposed FMOS definition in detail, and they approved it finally. The detailed design of FMOS was presented at the SPIE Conference held in Kona, Hawaii in 2002 (Kimura et el. 2003)
- Basic specifications, objectives and Collaboration Scheme
2.1 Specifications
In Table 1, key parameters of FMOS specifications are briefly summarize.
Table 1. Specifications of FMOS
2.2 Brief Summary of Scientific Objectives
Some representative scientific objectives are listed as follows. Concrete observing programmes of these scientific targets are by and large reported in the present conference. Descriptions of these items are briefly summarized in the past SPIE conference (Maihara et al. 2000).
1) Brown Dwarfs & Protostars : IMF and dark matter contribution in the Galaxy
(down to limit mag H = 22.5 mag.)
(accurate determinations of metallicity and temperature.)
2) Galactic Center Region
(kinematics and metallicity in the vicinity of the Galactic center)
(formation history of galactic bulge and local group galaxies)
3) Large-Scale Structure at High Redshifts
(probing activities of star formation at redshifts z > 1)
(systematic spectroscopic study of EROs )
(the Λ value by measuring velocity dispersion of clusters at z≧1.5)
4) Evolution of AGN/QSO Population
(studying obscured AGNs/QSO populations up to z= 5)
(nature of hard X-ray selected objects)
2.3 Collaboration Framework
The FMOS team consists of the Kyoto University/Subaru team, the UK-FMOS (Durham/Oxford/RAL) team, and the AAO-FMOS team.
Kyoto University/Subaru teamand AAO-FMOS teams have responsibility of developing the "Prime Focus Unit (PFU)",the "Prime Focus Corrector" and the "Fibre Positioner Subsystem: ECHIDNA" which includes:
* Mechanical Interface Structure for the Subaru Primary,
* Instrument Rotator,
* Cable-Twister,
* Shack-Hartmann/Autoguide system for mirror analysis/pointing analysis,
* Interface to Corrector
* Tube Piezo-based Actuators (ECHIDNA)
* Fibre Bundles for Autoguiding (7 bundles x 2 lines) and the related software
* Focal Plane Imager for field monitoring
* Housing, Control Electronics, and
* Fibre Deployment Software.
KyotoUniversityand University of Oxford, in collaboration with Rutherford Appleton Laboratory, have conducted design and fabrication of the "Near Infrared Spectrograph (IRS-OHS) Subsystem", which includes:
* Optical/Mechanical Design of Spectrograph,
* Fabrication of Optical Components (collimators, gratings, Special-type and normal-type Schmidt plates, etc. )
* Spectrograph Mechanical Structure with Adjustment Mechanisms,
* Cold Box, and
* Spectrograph Controller.
KyotoUniversity and Rutherford Appleton Laboratory have responsibility of designing and fabricating the "Spectrograph Camera (IRS-CAM) Subsystem",which includes:
* Optical/Mechanical Design of Camera Optics,
* Fabrication of Optical Components (lens system, lens mount, thermal-cut filter, coatings, etc. )
* Closed Cycle Cooler-based Dewar System,
* Hawaii2 Array Controller, and
* Camera Stage
University of Durhamand AAO-FMOS team have responsibility of developing the "Fibre Channel/Connector/Slit Subsystem", which includes:
* Fibre-Cable Design, Cutting and Polishing (Coating)
* Invar-basedSlit Units
* F/2-to-F/5 Converting Fibre Connector
* Back Illumination Subsystem, and
* Cable-Strain Relief
- construction process: Design and Fabrication of Subsystems
3.1 Construction Process of FMOSin FY2001 (April 1, 2001 -- March 31, 2002) and FY2002 (April 1, 2002 -- March 31, 2003)
* Detailed designing of the FMOS optical system as a whole started in 2001.
* Final design review of FMOS of PFU, IRS-OHS and IRS-CAM was held at Subaru-Hilo, Hawaii in April 2002.
* Detailed specifications of all optical components were fixed by the end of Dec. 2002.
*Some contracts of procurements of key optical components were made in FY2002, including the 1.4m collimator mirror substrates, due to a consideration of anticipated long lead time to complete them as well as financial resource scheme at NAOJ.
* Some of fabricationsand purchases of hardware components, such as optical fibre cables and lens glass for the prime focus correctorwere initiated in FY2002.
3.2 Construction Process of FMOSin FY 2003 (April 1, 2003 -- March 31, 2004)
* Full scale purchasing and assembling subsystems were started.
* Design of a new dome floor including the fibre cable circuitry from PFU to IRS-OHS was fixed in the "Fibre Review Meeting" at Hilo base in Sep. 2003.
* The basic framework of software developments in terms of respective areas of responsibility was fixed in the "Meeting" in Hilo.
*The fibre positioner system: Echidna, has been fabricated in AAO, as described by Moor et al (2003).
* The primary fibre bundle has been cut, polished, and AR-coated by the UK-FMOS team, mostly in Durham, as well as in Oxford.
* The corrector lens system has been polished and assembled in AAO.
* Fabrication of key optical components, including the 1.4m collimator mirror, the special-type Schmidt mirror (Mochida-Schmidt), the normal Schmidt plate, the mask mirror, and the mosaic grating, has been conducted in Kyoto and, all of which ahs been nearly completed by the end of FY2003.
* The assemble of one spectrograph system: IRS-OHS,as well as the spectrograph camera: IRS-CAM) has been started in KyotoUniversity. The cold box for IRS has also been tested in Kyoto.
* The assemble of anotherspectrograph system has been initiated in OxfordUniversity and RAL.
- assemble and commision Plan of overall system
4.1 Test Plans for PFU, Echidna, and Fibre Channel
* The new top-unit hardware (PFU) consisting of the top-ring interface, the instrument rotator, the wire twister, and the Shack-Hartmann subsytem, will be assembled in September 2004, and be delivered to Hilo in October 2004, which will be assemble with the corrector. There, the basic test using the revised software of PFU control will be made along with the corrector lens system.
* In January 2005, the new PFU will be attached to the Subaru top ring to prove the normal functioning of PFU, as well as to confirm the corrector performance.
* The Echidna system as a whole will be delivered in Subaru Telescope in March 2005.
* Two sets of fibre channels together with the strain relieves, connectors, and fibre-slit assemblies will be delivered to Subaru in March 2005.
* The fibre channels will be mounted on the Subaru Telescope in April 2005.
4.2 IRS Test Plan
* So as to accommodate two IRS-OHSs, the new floor above the infrared Nasmyth platform will be constructed by September 2004.
* The first spectrograph system together with the large cold box will be shipped to the "Subaru Dome Room" from KyotoUniversityin February 2005. The functional on-site test of the spectrograph system including the camera will be made in March 2005.
* The engineering test of the first FMOS spectrograph test will be made in May 2005 using a test fibre bundle (IFU-type) supposedly mounted on the Nasmyth focal station.
4.3 SoftwareDevelopment Plan
* The baseline of the OBCP software has been proposed by Eto, and the interface control documents defining specifications and conditions of the OBCP-vs-each subsystem will also be related by Eto.
* The Echidna-related software package including the auto-guiding controller will be developed by Smedley at AAO.
* Instrument control software of IRS-OHS together with IRS-CAM will be developed in Kyoto and Oxford.
* Data reduction software will be developed in FY2004 in collaboration with three groups. Akiyama at Subaru telescope will propose basic requirements, Smedley will create a primary software package for data reduction of spectral image, and Dalton will help refinement of software based on the 2dF experience.
4.4 Commissioningand GTO Plan
* The commissioning phase of FMOS will start off by the first PFU test run (two nights) in January 2005. Then the on-site assemble and test of each subsystem will subsequently followsit.
* The engineering run of the first spectrograph will be carried out in June/July, 2005 using the "observatory time". In this case, the test fibre bundle mounted on the IR Nasmyth focus may be used for the run, if the genuine fibre channel is not yet ready.
* The engineering run of the second spectrograph will be carried out in August/September (two nights), 2005, also using the "observatory time".
* From October 2005 to March 2006, we will carry out a couple of engineering runs (two nights each).
* After the confirmation of functionality of FMOS as a whole, the FMOS-construction teams are supposed to be endowed "GT-observing time" amounting to about 20 nights. Note that the observing programme has to be approved by the Subaru Advisory Committee in advance.
* It is assumed that the main body of GT-team is made of the FMOS builder group members. However, as we had experienced of organizing a GT-team in the first generation instruments, we would include additional collaborators who expressan interest in participating in the FMOS GT-team.
5. SUMMARY
The present status of the FMOS construction, the baseline schedules of fabrication of each subsystem, and the prospects of commissioning plans are briefly reported. Now, it is a good time to start discussion of GT-observing plans, and, I hope that the present Workshop would provide a basis of realistic GTO plans. In the meantime, I would like to organize, kind of, a “science team” among the Workshop contributors, which will eventually proposea set of “GTO programs” to Subaru Advisory Committee. Finally, if FMOS has become available with performance as expected, I hope that FMOSmightbe usedby SUBARU at a fairy high level,possiblyas many as 30 - 60 nights a year or so, depending on the TAC decision.
Acknowledgments
This Workshop was made possible by the supports of two sponsors. Theone is “The Daiwa Anglo-Japanese Foundation”. Here, The Daiwa Foundation supports UK-Japan collaboration projects by special grant to specific programmes. The other is “The COE Programmes of Physics and Astronomy at KyotoUniversity”. This is one of the categories of the Grants-in-Aid for Scientific Research of Monbu-Kagaku Sho (The Ministry of Education, Culture, Sports, Science and Technology).
references
Moore, A., Gillingham, P., Griesbach, J., Akiyama, M. “Spine Development for the Echidna Fibre Positioner,” in Optical and IR instrumentation and detectors, Proc. SPIE 4841, pp. 1429-1439, 2003.
Kimura, M. et al., “ Fibre-Multi-Object Spectrograph (FMOS) for Subaru Telescope II”, in Optical and IR instrumentation and detectors, Proc. SPIE 4841, pp. 974-984, 2003.
Maihara, T. et al., “ Fibre-Multi-Object Spectrograph (FMOS) for Subaru Telescope I”, in Optical and IR instrumentation and detectors, Proc. SPIE 4008, pp. 1111-1118, 2000.