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LIGO Caltech NewsThird Gravitational Wave International Committee Convenes In Paris
Dotted all about the planet right now are a variety of groups preparing to listen intently for the subtle ripples and vibrations of space-time. But shouldn't we ensure that these far-flung aficionados of the Cosmic Song first be able to hear each other? Wouldn't it be a shame if another supernovae, like the one in February 1987, were observed by the neutrino detectors and other observatories, but most of the gravitational wave instruments in the world were simultaneously down for maintenance and upgrades due to a lack of inter-communication? And imagine the flurry of mea culpas and embarrassment among these groups if, owing to ill-organization, one or more interferometers and resonant mass detectors saw a hint of a signal, but the crucial comparison of data by different groups took years because each group wrote the data to archival storage (magnetic tapes, disks, optical media) using different formats? And thus none of the analysis software or data could be interchanged or used together?
The gravitational wave community has wisely recognized that these issues, and many other thorny problems of organization, communication and cooperation, may play a major role in pacing the scientific product of this global effort to detect and exploit gravitational waves. Their solution is the Gravitational Wave International Committee (GWIC).
In Figure 1 at left, Alain Brillet of VIRGO presents the status of VIRGO. Next in Figure 2, Ian Halliday of the United Kingdom's Particle Physics and Astronomy Research Council enjoys a break in the proceedings. Then, Figure 3 shows (from left to right) Alain Brillet of VIRGO, Karsten Danzmann of GEO, Adalberto Giazotto of VIRGO, and Elisabeth Giacobino of the CNRS during a break in the meeting.
-- Promote international cooperation in all phases of construction and exploitation of gravitational wave detectors;
-- Coordinate and support long-range planning for new instrument proposals, or proposals for instrument upgrades;
-- Promote the development of gravitational wave detection as an astronomical tool, exploiting especially the potential for coincident detection of gravitational waves and other fields (photons, cosmic-rays, neutrinos);
-- Organize regular, world-inclusive meetings and workshops for the study of problems related to the development and exploitation of new or enhanced gravitational wave detectors, and foster research and development of new technology;
-- Represent the gravitational wave detection community internationally, acting as its advocate;
-- Provide a forum for the laboratory directors to regularly meet, discuss, and plan jointly the operations and direction of their laboratories and experimental gravitational wave physics generally.
GWIC's membership includes representatives of all the interferometer detector projects: ACIGA, GEO, LIGO, TAMA, and VIRGO; acoustic detector projects: ALLEGRO, AURIGA, EXPLORER, NAUTILUS, and NIOBE; and space-based detector projects: LISA.
LIGO Director Barry Barish and I attended the third of these twice-yearly meetings, this one held in Paris on December 19, 1998. It was a very robust affair.
Representatives of several of the national agencies responsible for funding the various efforts attended, presenting their current agency programs and their views on the international aspects of the field. They suggested areas where GWIC, acting as a body, might provide assistance and advice to help them in guiding their programs. Represented were the United Kingdom's Particle Physics and Astronomy Research Council ( PPARC ), the US National Science Foundation ( NSF ), the appropriate part of the German Max Planck Institute ( MPI ), Italy's Istituto Nazionale di Fisica Nucleare ( INFN ), and the French Centre National de la Recherche Scientifique ( CNRS). This was quite a significant gathering and presages clear communication of research priorities and emerging collaborative ideas between the scientific teams and their support agencies.
The several interferometer teams reported their status. By all accounts, 1999 promises to be a remarkable year, with the Japanese TAMA project commissioning its 300-meter interferometer, and with quite advanced construction and installation going on in GEO 600, VIRGO and LIGO. New plans are being launched also in Australia by ACIGA.
At left, Masa-Katsu Fujimoto describes the exciting progress in commissioning TAMA. Next, Bernard Whiting recounts the program in Australia.
One presentation offered a unique twist. Even as the scientists prepare to listen to the heavens, the scientists themselves are being focused on as objects of study. Harry Collins of the Centre for the Study of Knowledge, Expertise and Science, at Cardiff University in the United Kingdom, reported to GWIC on his sociological study of the gravitational wave community. Harry has been lurking in the shadows of almost every significant meeting on gravitational wave research for several years. His report was an opportunity for us all to hear from this "fly-on-the-wall" observer. His talk was most interesting, and we will devote a special column in next month's newsletter to an article by Harry. We cannot pass up the opportunity to return the favor and find out a little something about him! In the meantime, interested readers can check out Harry's website by clicking here.
Returning to the events of this latest GWIC meeting: the plans for LISA, a space-based interferometer, were described. This ambitious project is now the subject of consideration in both the US and Europe. Undisturbed by the gravitational field from mass on the Earth, it will probe lower frequency gravitational waves than those measurable from a ground-based instrument.
GWIC additionally hosts an international meeting focused on this experimental field under the name of the Amaldi conference series. GWIC reviewed and discussed the organization of the Third Amaldi Conference, slated to assemble at Caltech this July. Subsequent Amaldi meetings in Japan, France and the US were considered as well.
Next, the very important issue of inter-project collaboration on data analysis was discussed in a free-ranging session. This is a complicated matter, one in which the fine balance between competition and collaboration takes the center stage. Every scientist wants to be the first and only observer of something new. Yet every scientist also wants confirmation and the rapid development and progress of any innovative findings. It would be pointless to produce exciting results, bright with potential, only to see their luster dimmed as they sit neglected, incapable of confirmation. After all, we are each of us in this game from a passion to know the answers, the true answers. Confirmation, verification, replication--these are the three judges on the high court of science, and under their stern scrutiny all researchers must labor.
So this issue of data analysis collaboration is a vital one. A first step was taken several years ago when VIRGO and LIGO both agreed to use a common data format. This arrangement preserves the independence of each experimental team's data analysis, but supports a joint effort if one is agreed upon. This initial collaboration has now grown to include several other project's adoption of the format, as well as collaborative work in writing some of the pieces of software. At the GWIC meeting, discussion continued about how this might develop further in the future.
The venerable topic of resonant mass detectors was discussed, and plans for new generation spherical detectors and improved bars were the main focus. The resonant mass community is experiencing funding pressure from the larger interferometer projects, and GWIC is an important forum for discussion of the global program's balance.
After consideration of GWIC's relationship to other bodies, the tired delegates from around the world retired to a fine Parisian meal. The next GWIC meeting is to accompany the third Amaldi meeting in California in July. California wine and cuisine will definitely face a mighty challenge!