STUDY SUMMARY - IPMU

SUMMARY REPORT
WIDE FIELD FIBER-FED OPTICAL
MULTI-OBJECT SPECTROMETER (WFMOS)
location efficiency, evaluating survey completeness, deciding tiling strategy, and prioritizing observations
considering sky brightness and seeing. An observing tool that allocates targets to fibers
will be provided as part of the system software during the construction phase. The additional
steps described here involve interacting with this tool and performing any necessary additional
optimization.
The survey preparations and survey monitoring have many common elements in the two
primary surveys. A number of scientists will participate in the survey phase of WFMOS, and the
primary surveys will be conducted over the course of approximately five years (depending on the
yet-to-be-negotiated agreement with Subaru). The bulk of the day-to-day effort will be conducted
by post-docs under the direction of members of the current science team. The estimated
cost for this phase appears in the Management and Cost volume.
6.3 Installation and Removal
We anticipate that WFMOS observations will be interleaved with observations using other
instruments, including the HyperSuprimeCam. Removing WFMOS from the telescope will necessitate
the removal of the Prime Focus Unit from the telescope, disconnection of the fiber connector,
storage of a portion of the fiber optic cable on the side of the telescope, and possible removal
of the metrology cameras. Removal of WFMOS components from the Prime Focus Unit
will be required to allow the Prime Focus Unit to be reconfigured with HyperSuprimeCam. Installation
of WFMOS is essentially the reverse of this process. We estimate the Prime Focus Unit
can be removed from the Subaru prime focus in less than three hours and be accomplished entirely
with Subaru personnel in a manner similar to standard top-end unit exchanges.
The initial installation of WFMOS components in to the Prime Focus Unit is described in the
Prime Focus Instrument section of the Detailed Technical Design. Routine swaps of HSC and
WFMOS will be a streamlined version of this process. WFMOS is designed to allow the swap of
HSC and WFMOS components within the PFU to take approximately one full work day. This
estimate depends sensitively, however, on the detailed HSC design. Two members of the
WFMOS instrument team will be required to supervise the first two swaps. It is also prudent to
budget an additional few days for the first two swaps. Subsequent swaps would be accomplished
entirely with Subaru Observatory personnel. The detailed procedure and timeline for this process
will be developed before the WFMOS preliminary design review.
6.4 Additional Considerations
In addition to the Dark Energy and Galactic Archaeology survey observations proposed here,
there will be classically allocated non-survey observations. Although not formally requested to
do so by Gemini, we believe it prudent to consider the operational scenarios for these potential
additional observations. We envision that many of these surveys will have long-term status and
be queue scheduled. The rest will be a broad range of observing programs proposed by PIs from
within the Gemini and Subaru communities. These could also be queue scheduled, or the observers
may be given fixed nights and visit the telescope. WFMOS can accommodate these observations
with no additional software cost by using the System Software observing preparation tools
and the Package A data reduction pipeline. The operation of WFMOS will not be very different
from that of other fully automated multi-fiber spectroscopic survey instruments, such as FMOS,
2dF+AAOmega, and FLAMES.
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