Subaru Telescope New Development Group
Date / Time: October 8, 2013 13:30 - 15:30 (HST)
Place: Hilo office room 104A+B
[ Scope of Decommission Discussions, Timeline ] * Timescale of decommission? Before TMT is in operation, some instrument would lose its competitiveness. However, if we stop operation of some instruments before TMT's start of operation, we would lose some functions without any alternatives. - We should discuss the instrument plan for the entire 2010s, until the TMT starts operations. - In the project week we will be asked the decommission plan in 2010s. - Subaru users meeting in Jan. 2014 is not the opportunity for the final decision about the entire instrument plan, except for FMOS on which the decision should be made by Jan. 2014. * How much of the budget would be reduced in the next 10 years? It is one of the boundary conditions to discuss the instrument plan. - If we want to keep some science capability, we should try to maintain the budget scale to achieve that. The reason why we need to consider the decommission is not due to the reduction of the budget, but because the science goals of Subaru Telescope are changing (to large survey type science cases). - As a basis of the discussions, we may assume we can keep the budget scale of the current Subaru Telescope for the entire 2010s. - We would need to call international partners to maintain the current budget size. [ Shift to Survey-type Instruments ] * Shift to survey-type observations means smaller number of instrument exchange? - Basically yes. * Survey instruments - data pipeline plan? - For HSC and PFS, building data archive and publishing catalog are important to maximize their science output. HSC team is developing a pipeline for the SSP program. How much we can support general open-use program is TBD. We are discussing with the HSC team and trying to establish a team. - For other existing facility instruments, we do not plan to provide reduced data and catalog. - For future facility instruments such as PFS and ULTIMATE- SUBARU, providing reduced data and catalog processed through the pipeline is one of the goals. * If we push ourselves into survey-oriented observations, it is somewhat inevitable to reduce variety of Subaru instruments. [ Priority among Considerations ] * Is the workload with the current instrument too much? If yes, we need to reduce the workload. - Is is difficult to quantify the workload in future. * Why is the number of publications with Suprime-Cam keep increasing? - It mainly comes from the use of the data archive (SMOKA), probably used by non-Japanese researchers. - Note that the approved program with Suprime-Cam is almost flat or is slightly decreasing. The increasing number of annual publications with Suprime-Cam comes mainly from the re-use of past observation data. - The number of papers by Suprime-Cam is outstanding, but there should be many aspects to be considered, such as development of new technology, education etc. - We will keep Suprime-Cam for the next two years. - Prime Focus is a unique capability among 8-10m class telescopes (at least until LSST). So wide-field surveys using prime focus instruments make sense. [ PI-type Instruments, Instrument Development ] * Can new PI-type instruments substitute or update functions of facility instruments? - Most PI-type instruments are designed for some specific science cases. - We can not expect high reliability for all of PI-type instruments compared to facility instruments. * Another thing we should consider is what the science community wants. Building interesting and ambitious instruments based on new technologies are important to keep Subaru competitive and drive development of further future instruments (for TMT and others). How much the science community understand and support building such PI-type instruments? - The number of PI-type instruments for Subaru is increasing. - Recognition of the importance of keeping the instrument development among the entire community is not enough. The support for instrument development by NAOJ HQ has been very limited for years. * Subaru's role as a test bed for new instruments should be considered in future. * Important thing is to keep competitiveness of Subaru’s suite of instruments by introducing new instruments. * Balancing instrumentations for optical and for infrared is important. [ Time Exchange, Instrument Transfer ] * Is there a possibility to increase of time exchange? - Arimoto: Yes. We will try to increase fraction of time exchange and to stop accepting proposals from non-Japanese researchers. - Number of proposals for all Subaru’s instruments are almost identical. If we stop operations of some instruments, twenty percent of time exchange may not be enough to compensate the loss of instruments. * Functions of some instruments could be substituted by time exchange program. * Uniqueness of instruments. Currently FMOS has unique capability and UH extensively uses FMOS. * If we provide survey-type instruments to VLT community, Japanese community would lose some fraction of nights for surveys. - Combining Subaru's survey instruments with the instruments in other telescopes which have different capabilities should increase the values of the scientific outcomes. * We started discussion on the possibility of the transfer of HDS to Gemini. [ Early Decommission of FMOS ] * Presentation by Takato-san: - PFS team is thinking about putting four spectrographs on IR-M3 floor by adding new floor. We may be able to reduce some cost if we remove FMOS and put PFS spectrographs on IR-TUE floor. Also, coolant FMOS is using will be enough for PFS. Reducing observatory workload is another point. Maintenance could be easier in IR-TUE floor. - Have we got the enough science return from FMOS? - There will be more than three years without prime-focus spectrograph. - Interval between four spectrographs needs to be shorten to keep the schedule. - We need to make a decision by Jan. 2014 to keep the PFS schedule. * Q&A and Discussions: [PFS Plan] - Is introducing four spectrographs in one year feasible? - Spectrographs will be built in France and in Hawaii only re-assembly and test will be made. It is certainly challenging but is not completely unfeasible. - Is the first-light of PFS in 2017 really feasible? We need to know the feasibility of the PFS project before we start thinking the FMOS decommission. - If we stick to FMOS we may lose PFS due to difficulty in flooring. - Originally we planed to keep FMOS until PFS becomes stable. But keeping FMOS along with commissioning of PFS could be difficult for Subaru (infrastructure, workload, budget etc.) - Is it possible to start engineering obs. with one spectrograph? - It would be possible, but spectrographs will be ready independently from the flooring. - How about placing two of four PFS spectrographs on the IR-M3 floor and put the other two spectrographs on the IR-TUE floor later? - That plan may work, although the commissioning process will become more complicated. - If the schedule of PFS delays, the project won't be able to keep the team, and the project will go into a serious problem. - Staffing Plan for PFS?: two people to be hired by Subaru from the beginning of the commissioning. - More technicians' time would be required to keep PFS spectrographs operational. - We need to carefully watch the quality of the instrument to reduce maintenance load. [Science Cases with FMOS] - If we carry out FMOS observations rather intensively in S14B and S15A, can we cover significant science cases with FMOS? - Some studies combining HSC imaging data and FMOS follow-up spectroscopy would be lost by early decommission of FMOS. - Galaxy mass-metalicity relation is one of the important science cases for FMOS, and researchers have carried out (or are carrying out now) such programs. - Star-formation sciences with FMOS could be explored more.