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The Future of Gemini Instruments

The Aspen instrument program is a multi-faceted development effort, with a foundation of existing AO-fed imagers and spectrometers as well as mid-infrared instruments. They will provide unprecedented sensitivity thanks to the unique infrared optimization of the Gemini telescopes. Building upon this foundation will be three new instruments that have been the subject of a number of studies over the past year. These include an Extreme Adaptive Optics Coronagraph (ExAOC), a High Resolution Near-Infrared Spectrometer (HRNIRS), and a Wide Field Multi-object Spectrometer. Given the science ambitions expressed by the Gemini community through the Aspen Workshop, these new instruments are by necessity ambitious, technically challenging, and expensive. These innovative new instruments will place the Gemini community at the forefront of research in such areas as extra-solar planets, dark energy, and galactic formation and structure. In addition, a study has been completed that examined the feasibility of building a ground-layer adaptive optics (GLAO) system for Gemini-North which, if pursued, will be incorporated into a facilities upgrade program for both telescopes. The Aspen instrument program therefore involves far more than just building new instruments, it includes:

  • Modifications to existing instruments
  • The use of a visitor instrument
  • The design and construction of bold new instruments and facilities
  • The implementation of new methods for executing large observing campaigns
  • The development of new partnerships that will help answer the questions posed in Aspen

The next critical steps in the Aspen development program are articulated in a Gemini Board Resolution, passed earlier this week. It summarizes discussions and activity conducted over the past two years and directs the observatory to pursue a combination of conceptual design studies, construction activity, and a site testing campaign on Mauna Kea. More specifically, the Board has decided to go forward with the ExAOC. Gemini anticipates entering contract negotiations to build and deploy this advanced instrument, which will be capable of direct imaging and spectroscopy of extrasolar planets. In addition to ExAOC, several announcements of opportunity to participate in conceptual design studies will be posted on Gemini’s Web site in the near future. These will further expain the the technical requirements for instruments that remain under study. Briefly, these announcements of opportunity will be the first steps in defining:

  • Two competitive concept-level design studies for the Wide Field Optical Multi-object Spectrometer (WFMOS) - intended to support research in key areas including dark energy and galactic archeology.
  • Two competitive concept-level design studies for a near-Infrared Precision Radial Velocity Spectrometer (PRVS) – intended to support a key component of the HRNIRS science case, namely the search for terrestrial-class planets around low-mass stars.
  • A site testing program, targeting high-resolution measurements of the ground-layer turbulence profile above Mauna Kea. This will support the potential deployment of a GLAO system at Gemini-North.

All of these studies will be completed in time for consideration at the November 2006 Board meeting, when a decision will be made to either pursue WFMOS or, in the event of an unsuccessful study phase, build HRNIRS instead.. A decision to go forward with the GLAO program is pending results of site seeing measurements taken through mid 2006. Similarly, a decision regarding the construction of PRVS depends on the outcome of the studies for this instrument, which will start soon. Components of the Aspen Program not mentioned in the Board Resolution also include the augmenting of GSAOI and FLAMINGOS-2 with specialized filters to support searches for so-called “First Light” objects in the early universe, and the use of the high resolution mid-IR spectrometer TEXES (built by the University of Texas) on Gemini-North in 2006, which among various science applications will support studies of gaseous proto-planetary disks, a major facet of the Aspen science mission.

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Gemini Board Resolutions

I. Introduction

The "Aspen process" engaged a large number of astronomers throughout the partnership in a new approach to the future of Gemini instrumentation. National representatives met, and then partners' delegates met in Aspen, to discuss the key science questions that we now recognize, and to which we might obtain answers with suitably powerful observational attacks. The Aspen process, detailed in the document: "Scientific Horizons at the Gemini Observatory: Exploring a Universe of Matter, Energy, and Life" identified many of these key questions, and the types of instruments that might be designed and built to address them. From a suite of almost four dozen instruments identified during the initial discussions in the science theme panels, a prioritized selection, based on new scientific challenges, was developed for further discussion. This list included eleven instruments and two major facilities (new top ends) that would be required for some of the proposed instruments. The Gemini Science Committee discussed the science goals, the capabilities of the proposed instruments, and rough cost estimates provided by the Observatory and independent reviewers in October 2003. Based on this information, the GSC recommended three top-priority instruments, including a wide field multi-object spectrograph (WFMOS), a high-resolution near-infrared spectrograph (HRNIRS), and an extreme adaptive optics coronagraph (ExAOC). Five additional capabilities were identified for further feasibility studies or possible negotiation for importation of an existing instrument to Gemini. At its November 2003 meeting, the Gemini Board endorsed the GSC report and directed the Observatory to undertake design studies for ExAOC and HRNIRS, feasibility studies for WFMOS and ground-layer adaptive optics (GLAO), and to explore modifications of existing or already planned instruments that would address key Aspen science questions.

These studies have yielded design proposals for ExAOC and HRNIRS and some cost estimates for all four capabilities, including WFMOS and GLAO. In parallel, the Board met in a retreat in September 2004 to discuss the operational needs of the Observatory and the costs and challenges of the new Gemini instrumentation. In concert with the Executive Agency and the partners' funding agencies, the Gemini Finance Committee identified a funding envelope for the Aspen instrumentation initiatives of $75M. At its May 2005 meeting, the Board recognized this envelope would be inadequate to design, construct, and commission all four instruments on the Gemini telescopes.

Also at the May 2005 meeting, the Board listened to presentations on the science opportunities enabled by each of the four instruments, and reviewed a number of options devised to address as much science as possible within the funding envelope. The Board sought the advice of the GSC, who conducted an 8-hour telecon in early June, and recommended a series of priorities to maximize the science opportunities. The Board accepts these recommendations, and looks forward to broad-based participation by the partners in the design, construction, and exploitation of the instruments that will be built and deployed in the coming years.

The Board notes in particular that construction funding will be committed at this point for ExAOC, and will require additional information before committing to construction funds for the remaining instruments.

II. WFMOS

The Board agrees with the GSC that if it proves feasible, WFMOS must be built because among the several instruments, it offers the most transformative science opportunities. The Board directs the Observatory to proceed with negotiations with the Japanese community on a possible partnership with Subaru. Indeed, the Board looks forward to increased engagement with the Japanese community in mutual research endeavors. Because of the magnitude and uncertainty of the costs of the WFMOS instrument, software, and data flow, the Board requests that two openly-competed concept design studies be initiated.

Further, the Board requests that the results of these studies be summarized and presented to the GSC for scientific comment and community input in time for a meeting in October 2006. Subsequent to the GSC deliberations, the Board expects the Observatory to present a programmatic presentation, including both science relevance, managerial processes, and data archiving, reduction pipelines, and dissemination models to the Board at the November 2006 meeting.

The Board also recognizes that there are numerous operational issues that must be addressed in consequence of undertaking a new partnership with our Japanese colleagues, and that we need to understand these issues as soon as possible. The Board therefore charges the Director to develop a white paper that addresses the goals, metrics, and milestones with timelines that will guide the discussions with Subaru. The Board echoes the GSC's desire to have a clear articulation of the arrangements that promote successful scientific, technical, operational, and cultural collaboration, and asks to have the white paper available for discussion at the November 2005 Board meeting.

The Board expects that final memoranda, actions, and principles of collaborative commitment be captured in a detailed document by October 1, 2006. The Director shall then circulate this document to the Board and to the funding agencies for their consideration. The Board anticipates that at the November 2006 meeting the partnership will determine whether to commit construction funding to WFMOS on the basis of the design studies, collaborative working agreements, and justifiable cost estimates for the total WFMOS project and its two key science issues, dark energy and the Galactic archaeology.

III. ExAOC

The Board also agrees with the GSC that the search for planets around other stars is a key science theme, and that Gemini's optics provide an excellent platform for an advanced adaptive optics capability. As discussed in Board Resolution 2005.A.1, the Board has endorsed the Director's selection of the team to build the ExAOC, and directs the Observatory to commence contract negotiations to construct the instrument, consistent with available funding and committment authority.

IV. HRNIRS

The Board recognizes that the available funding envelope, while very generous, is inadequate to support construction of the top three priority Aspen instruments, and the Board cannot endorse at this time an award for the construction of HRNIRS as proposed by either of the two teams. The Board recognizes that a significant fraction of the key scientific areas of inquiry proposed during and subsequent to the Aspen meeting would be unrealized without this instrument. If the WFMOS proves to not be feasible at the November 2006 meeting, the Board wishes to then undertake the science enabled by HRNIRS. Specifically, the Board endorses the resolution of the GSC:

"The GSC sees the WFMOS Concept Design Review as a critical point within the Aspen decision tree. If continuing with WFMOS into the build phase is deemed to be unfeasible at the time of this review, then the GSC strongly recommends that the Observatory proceed immediately with the procurement of HRNIRS. However, it would be prudent for the GSC to rapidly reassess at this point the various HRNIRS options (full-HRNIRS, HRNIRS[R=70K], HRNIRS[MCAO-MOS]), to determine whether they will still be timely and/or competitive by the end of the build phase (~2013)."

Because the search for low-mass planets is such a timely and exciting topic, the Observatory recommended that a component of HRNIRS be explored for rapid implementation, and the GSC endorsed this concept, now referred to as the "Precision Radial Velocity Spectrometer" (PRVS). The Board agrees with this recommendation, and directs the Observatory to quickly undertake two competitively-selected concept design studies, with costs, schedules, and capabilities presented to the Board as soon as possible; the goal should be in time for GSC review prior to the May 2006 meeting of the Board. Certainly such discussions must occur no later than the November 2006 Board meeting, following GSC commentary.

V. GLAO

Finally, the Board wishes to retain the option of proceeding with possible deployment of ground-layer adaptive optics, GLAO, and directs the Observatory to commence testing atop Mauna Kea to determine if the site is amenable to such corrections of image quality. The Board expects that such work would commence in mid-2005, and wishes to be informed of the outcome of such work at its November 2006 meeting.

VI. Conclusion

The Board has asked for considerable additional information in terms of an operational white paper, two pairs of concept design studies, and site testing. The Board's goal therein is to enable us to decide how to allocate the remaining Aspen instrument funding in the most rational and scientifically productive manner at its November 2006 meeting.

The scientific horizon for Gemini made available through the Aspen process and the contributions made to the partnership are likely to lead to major advances in science. The Board is very grateful to all the people and institutions which have made this possible, from national pre-Aspen teams to the Aspen participants, and including, of course, the Observatory staff and the GSC.