NSF Gravitational Physics
The LIGO project is nearing completion. In mid 1999 two interferometers are scheduled to be installed at the Hanford, Washington site and shortly thereafter a third is to be installed at the Livingston, Louisiana site. By the end of 2001 all three interferometers are planned to operate in coincidence with a strain sensitivity of . In anticipation of the operations phase of LIGO, NSF has been encouraging the scientific community to participate in the use and development of LIGO.
On June 25, 1996, NSF convened the Panel on the Long Range Use of LIGO (henceforth to be called the Panel). The Panel was asked to advise NSF on the policies, procedures and resources required to stimulate and support outstanding investigations at LIGO. The Panel was also asked to comment explicitly on the respective roles of the LIGO Project and the NSF in the organization, review, and funding of the scientific observations and the detector R&D. Thirdly, the Panel was asked to estimate the size of the users community and to advise on the funds that would be required over the next decade for LIGO to be an effective user facility. The Panel members were drawn from several areas of the physical sciences including, of course, gravitational physics, but also including disciplines requiring large facilities. Appearing before the Panel were representatives of groups planning to use LIGO, heads of gravitational wave facilities abroad, and the Chair of the LIGO Research Community.
The Panel made recommendations on organization, procedures, policies, data handling and funding. The Panel's report covers a broad range of issues and includes 13 recommendations. I will discuss only a few of these here. The complete report is available on the Web at http://www.nsf.gov:80/mps/phy/ligorpt.htm.
The Panel began with the premise that the essential near-term priority for LIGO is to achieve a definitive detection of gravitational waves. This achievement will validate the system and inaugurate the field of gravitational wave astronomy. Despite the impressive achievements for the initial LIGO detector, greater sensitivity may still be required for the unambiguous detection of astronomical sources. Even if signals are detected with the initial detector, a greater signal to noise ratio will be required to pursue gravitational wave astronomy. Therefore, in the medium term accompanying and following the commissioning, the LIGO Project must be focused on an aggressive R&D effort to achieve an improvement of 10 to 100 times greater strain sensitivity. The Panel noted that, as part of this effort, it is imperative to develop extended national and international collaborations in order to bring the best possible people, ideas and technologies to bear on the detection of gravitational wave radiation. The Panel recommended that these collaborations be integrated with centralized R&D coordination and LIGO Project management. The collaborations developed during this intermediate term will form the basis of the community that will carry LIGO into the longer term marked by the transition of gravitational wave detection into an observational science.
The Panel recommended that the LIGO Project should evolve from the current single management into two distinct entities: 1) a LIGO Laboratory and 2) a formally organized initial Collaboration. The Laboratory will provide the infrastructure that makes it possible for instruments to be developed, built and operated. The Collaboration will build, commission and exploit the initial detector and develop improvements to enhance its sensitivity. The Panel recommended that the Collaboration devise its own plan for internal governance, including clear procedures for the admission of new members. It will be essential for the Collaboration to have a spokesperson who will communicate with the outside community.
The Panel recommended the formation of a Program Advisory Committee (PAC) to provide advice on the formation of the Collaboration, the acceptance of other collaborators, the selection of R&D projects and the assignment of priorities. The Panel proposed that the PAC be part of the NSF review process for LIGO related proposals.
Following this advice, the NSF recently asked the LIGO Project for its opinion on several pending LIGO-related proposals. In formulating the Project opinion, Professor Barish, head of the LIGO Project, obtained an internal staff review of the proposals and then asked the PAC also to review them. With this action, the PAC review became part of the NSF review process.
All of these pending proposals will also be processed through the normal NSF peer review procedure. The evaluations by the LIGO staff and the PAC will be forwarded to the NSF reviewers. This augmentation of the NSF review procedure appears to be working well and, perhaps with some minor modification, will become the standard for processing LIGO-related proposals.
The Panel on the Use of LIGO recognized that LIGO is a national facility and has an obligation to make its data available to those who can make effective use of them. The Panel also recognized that the detection of gravitational radiation will be of such monumental importance that we can ill afford the report of a false signal.
Therefore, the Panel suggested that community involvement in data handling during the initial stage be achieved by drawing into the Collaboration those who would work directly with the in-house LIGO team in developing data analysis tools. During this stage, data will be given only to the Collaboration and publications will require the approval of the Collaboration and in some cases the LIGO Principal Investigator. The Panel noted that the possibility of developing distributed data products should be considered after gravitational radiation events have been detected and the detectors are well understood.
The Foundation has encouraged the collaboration of outside scientists with the LIGO project first to contribute to the initial detector and second, to address the R&D required to improve its sensitivity. The effective use of NSF resources will involve collaborations with the LIGO Project and later with the Collaboration. These arrangements are being codified through substantive memoranda of understanding (MOUs) among the parties involved. These MOUs are the instruments through which NSF will know that each party understands and agrees to its role and scope of activity and the role of its collaborators.
The development of advanced detectors, those beyond the initial LIGO detector and its enhancements, will also require a coherent effort. Plans for handling such proposals await the formation of the Collaboration and the establishment of proper linkages with the Collaboration and the LIGO Laboratory.