Science with Giant Telescopes—A Report on the Community Workshop

The discussion surrounding the issue of giant telescopes has brought into sharp focus the broad range of community perspectives on public-access facilities. The Giant Segmented Mirror Telescope (GSMT) was the highest priority ground-based recommendation of the previous (2000) decadal survey. Two “private” projects, the Thirty Meter Telescope (TMT) and the Giant Magellan Telescope (GMT), have begun technical development and fund raising. As described in the previous issue of Currents, both projects have recently approached the community (see “AURA receives letters from GMT and TMT boards”), requesting public participation, support, and funding.

Meanwhile, the NSF Senior Review observed that NOAO was moving too aggressively towards such participation at the expense of the current facilities. Wayne van Citters, then Director of the Division of Astronomical Sciences at the NSF, asked NOAO to act as a program manager for public participation in GSMT, including the development of a report (a community “Design Reference Mission”) that specifies and justifies community participation in these projects and in the use of these facilities. As a step towards this goal, NOAO, through the GSMT Science Working Group and with the endorsement of the NSF, held a workshop, “Science with Giant Telescopes: Public Participation in TMT and GMT,” on 15-18 June in Chicago.

Science with Giant Telescopes Workshop:

At the Chicago workshop, the first half-day was taken up with presentations describing the high-level design, instrument concepts, and status of the GMT and TMT projects as well as the ESO project, the E-ELT. The next 1.5 days included both science sessions—short presentations on possible observational projects—and programmatic sessions, in which presentations on “lessons learned” were followed with plenary discussions. The final half-day concluded with a wide-ranging discussion of several important questions that had been raised during the workshop.

Approximately 100 astronomers attended the workshop, including about 65 from institutions outside the TMT and GMT partnerships. The agenda, presentations, and pieces of the report as it is assembled, are available at http://www.gsmt.noao.edu/swgt.php.

Many interesting possible science projects were presented, such as mid-IR studies of nearby sites of star and planet formation, stellar populations and their histories in nearby galaxies, and large-scale structure and the formation of the first galaxies. It was clear that both the collecting area of a GSMT and its ability to reach the diffraction limit will drive important breakthroughs in all of these areas. It is also clear that synergies with JWST, ALMA, LSST, and other future facilities strengthen the need for the capabilities that these telescopes will provide.

Highlights from the Programmatic Sessions:

Ground-based observatories have lagged spaced-based facilities in developing the ability to archive reduced data. The reasons are, at least partly, technical: the plethora of instruments and their modes, the need to address different and variable environmental conditions, and the widespread use of classical observing all contribute to the challenge of producing uniform, high-quality reduced data. In addition, maintaining and operating an archive is a significant cost. Although everyone agreed that raw data, calibrations, and metadata should be kept, opinions about the cost-effectiveness of providing a public archive of reduced data varied considerably.

There was also an extensive discussion of the relationship between federal participation in GSMT telescope projects and future access to current (smaller aperture) facilities. Representatives from both Carnegie and Caltech spoke about their intentions to divest themselves of portions of their current facilities. The community might see this as an opportunity to incorporate increased access to these facilities into the national system. It is clear that broad community support for future federal investment in a giant telescope will require maintaining community access to a suite of facilities that is scientifically balanced over a range of apertures.

The workshop was a very productive beginning to this dialog. There will be future GSMT workshops, and additional opportunities for the ground-based O/IR community to learn about the TMT and GMT projects, to discuss the issues, and to make their voices heard. Watch Currents for future announcements on this topic.