| The LIGO
LIGO Livingston Observatory NewsEighth LSC Meeting Convenes in Louisiana
Passing Milestones: The Third Engineering Run at Livingston
A Journey Through Light
[Editor's Note: For a week in mid-March, the peaceful and rustic setting of the White Oak Plantation in Baton Rouge played host to a swarm of eager, science-impassioned LSC members coming together for their eighth meeting. To chronicle this event, we have fashioned a rare double article, a compound perspective, two reports joined to give the whole story. First-up is an objective, issue-specific account by Collaboration Spokesperson Rainer Weiss. Rai describes the highlights and prominent concerns of the meeting, and from him we also learn the vital functions of the LSC. Following that is a more personal narrative from Linda Turner, head of LIGO's document control center, visiting the LSC for her first time. Fascinated by the interactions she saw, Linda had the unique idea of asking the members how they actually felt about the event. The responses she received reveal the excitement and strong human conviction that often drive the scientific quest.]
The eighth meeting of the LIGO Scientific Collaboration (LSC), just completed at the White Oaks Plantation in Baton Rouge, Louisiana, was the most active and interesting collaboration meeting so far. The pleasant and convivial surroundings, a reproduction plantation building and grounds used for weddings and other large functions in the greater Baton Rouge area, may well have contributed.
Above: The White Oak Plantation and scenes from the eighth LSC meeting in progress.
It is evident that the LSC has become centrally involved in all aspects of LIGO. The four principal areas are:
1. The operation and commissioning of the initial LIGO detector.
Through the Detector Characterization group, LSC members have responsibility for operations during the engineering data runs and the use of diagnostic software, some of which has been developed by the LSC for general use. LSC members have taken on specific studies of the detector and the environmental monitors. There were several interesting papers from the Second Engineering Run (E2) as well as the just completed E3 run (also reported on this month). These papers dealt with a range of issues, including: the long term optical cavity performance, the effect of the tides on the interferometer control system, studies of the test mass suspensions, long term measurements of the cavity alignment fluctuations, system calibration, techniques to search and catalog transients in the data, methods of cataloging narrow lines in the data, and studies of the timing between the two sites.
2. The validation and test of the LIGO data analysis system (LDAS).
Chaired by LSC members and guided by the Software Coordinator, the LSC and the LIGO Laboratory have completed two mock data challenges (MDC). The first of these was to test software that has been written to precondition the data before it is analyzed for source waveforms--the so called Data Conditioning API. This conditioning performs rudimentary but necessary simple functions on the data stream such as averaging, Fourier transformation, heterodyning, etc., which precede source specific data analysis.
The second MDC established the critical function of testing the ability of LDAS to work with the routines developed for the LIGO Analysis Library (LAL). The LAL contains routines, many developed by members of the LSC through the Astrophysical Source Identification and Signatures group, to search for astrophysical sources such as inspirals, bursts, periodic and stochastic sources. Both of the MDC were successful and have established that the LSC and the Laboratory staff responsible for the software can work well together.
3. The completion of the advanced LIGO detector planning, and National Science Foundation review.
The careful planning that has emerged from the Detector Development groups involved with seismic isolation and suspensions, high power lasers, and optics and interferometer configurations has been brought together to create a coherent program for research that will lead toward a greatly improved second generation detector. The proposed program is carried out both in the LIGO Laboratory and at various LSC institutions. Significant components will be done in Europe at the GEO facilities. The proposed detector will provide roughly a factor of 15 improvement in the maximum sensitivity and a factor 10 broader search band than the initial detector. Current estimates are that compact binary coalescences will be observed with high probability at a rate of a few per year.
The National Science Foundation committee that reviewed the program in January gave the proposed technical and management plan a strong endorsement, highlighting the critical role played by the LSC.
4. The inauguration of the LSC astrophysical source upper limit groups.
The new activity inaugurated between the previous meeting at Hanford and this latest one is the formation of groups to set upper limits on burst, inspiral, periodic and stochastic background sources using engineering data to be taken in Fall 2001. The function of these groups is two-fold. First, to test the LIGO Data Analysis System in preparation for future science runs. Second, to write the first significant astrophysical limit papers using the data from the engineering runs. These papers may not be earth-shaking but they will be the first scientific results derived from LIGO and should be interesting. They should be able to say that certain processes one could imagine do not occur in nature or at least within a certain distance of the Earth.
The groups are composed of a blend of LSC scientists who have concentrated on software development, and those who have been working on installing and commissioning the initial detector. Following the prescribed procedure for all LIGO data analysis, the groups's first task was to write a data analysis proposal open to the collaboration for review by the LSC Executive Committee. The proposals have been accepted and work began on the last day of the LSC meeting. These were the first face to face meetings (rather than the prior ear to ear phone meetings) of these groups.
The meeting was organized by the LSC Software Coordinator. The initial activities of the groups are to establish the requirements of the instrument and data so as to be able to perform the specific search analyses: the detector power spectrum, the calibration, the types of statistics, the injection of test waveforms, etc. The other key function is to take inventory of the software already written within LDAS, LAL, and in the detector characterization group, and also to adapt it to the source specific upper limit evaluations. At this eighth LSC meeting, the groups began iterating their proposals and making those hard decisions over priorities, deciding what actually gets done in the first round and what must be deferred. Several of the groups have targeted the beginning of the summer for initial software tests.
This March, I made my first pilgrimage to the LIGO Scientific Collaboration and experienced first-hand the bubbling energy and enthusiasm generated by the intellectual stimulation, noteworthy accomplishments, and collective problem-solving of over 100 scientists and engineers. Whether in complete assembly or smaller working groups, one sensed a vibrancy in the air, an expectancy and promise for the discoveries anticipated by LIGO.
And what was I doing there? My task was to bring a satellite Document Control Center (DCC) to the conference and assist in the submission and processing of all the speakers' presentations so that these could be expeditiously posted on the web. And as a fringe benefit, I also looked forward to meeting many of the people whose names and voices I was familiar with from dealings in email or over the phone, but whom I had never before had the pleasure of meeting face to face.
Ordinarily, creating a mini-DCC at the Livingston site would be a fairly straightforward affair. But this meeting convened at the charming, tranquil, and decidedly un-high-tech White Oak Plantation (at left, above), creating a few challenges for us technically. My "office" (at right) was reminiscent of one of those hasty "MASH" field encampments. I sat in the middle of an outside patio with a canopy overhead, surrounded by a color printer, my computer, hanging electrical wires, cables, and a single 26k modem line--a pretty amazing setup! Still, with only these bare-bone rudiments of technology available, and the single internet phone line, it meant a hundred other bodies were left incommunicado. One person asked in disbelief how they could all be reduced to use of a solitary payphone! Unheard of! Others exhibited similar withdrawal symptoms over their detachment from email and global communication. But gorgeous garden surroundings, delightful rooms, and gracious Southern hospitality offset whatever was lacking in modern electronic conveniences.
By the end of the conference I had collected and processed over half of the presentations, all ready to be turned over for web posting. But more importantly, I came back having made new friends, time spent with old friends, and the DCC--perhaps a "black hole" for all things paper--became more personal to LIGO's collaborators.
Personally, I was fascinated by the variety of expertise, scientific disciplines, education, and cultures comprising the LIGO collaboration. Upon returning home, I asked some of my familiar colleagues, as well as those I had met for the first time, to share some of their perspectives on the week-long event. Here's what a few of them had to say...
"The LSC meeting is a good way to keep in touch with the international community and stay informed of broader aspects of the LIGO project than the narrow aspect I work on. Hearing talks on the science--as well as the engineering aspects--is beneficial because it keeps the engineering work in perspective. It is also a good opportunity to let people in the community know what I am doing." -- Peter Beyersdorf, Stanford University
"I am always looking for signs that the "C" in LSC is taking foot. By this I mean scientists of widely varying disciplines are working coherently on different tasks and projects which are loosely held together by the fabric of LIGO." -- Kent Blackburn, LIGO-Caltech
"Getting to know what the rest is doing...getting the 'big picture.'" -- Gabriela Gonzalez, Penn State
"Conferences like the LSC give an opportunity to see familiar colleagues in person and meet new ones." -- Anthony Rizzi, LIGO-Livingston Observatory
"Brings together colleagues working in similar areas at diverse locations, allowing exchange of ideas and detailed face-to-face discussions." -- Norna Robertson, GEO 600
"This is the main structure for coordinating the work of the LSC. I learned what my colleagues are dong, and was able to give and receive advice on LIGO-related research." -- Peter Saulson, Syracuse University
"I got to talk face-to-face with many colleagues from other institutions, and in some cases, sit down and sketch out some ideas together--something that can't be done over the phone... it seemed like we were much more able to make real decisions, all sitting in the same room." -- Peter Shawhan, LIGO-Caltech
"LIGO is entering an exciting phase of its development. The interferometers are coming on and before long we will be reaching sensitivities capable of doing science. This is great!" -- Jim Brau, University of Oregon
"We are close to having actual astrophysical data after so long, and you could feel the excitement at this LSC conference." -- Gregg Harry, Syracuse University
"I was enormously impressed at the rate of progress in some traditionally slow areas, especially with software and tools development." -- Nergis Mavalvala, LIGO-Caltech
"We've come a long way in the last three and a half years. Although we still have a ways to go, I'm now quite optimistic that we will be fully ready as a scientifically effective collaboration for next year's science run." -- Keith Riles, University of Michigan
"I thought this was the best run, best content LSC meeting yet. It made me feel that the LSC has really gotten rolling." -- Rick Savage, LIGO-Hanford Observatory
"I'm impressed how well members of various LSC institutions work together." -- Peter Shawhan, LIGO-Caltech
"I think the most exciting thing about LIGO is its scale. It is not just the biggest detector being built, but it is three of the biggest detectors being built. Of course, the challenge of operating it is equal in magnitude..." -- Peter Beyersdorf, Stanford University
"LIGO is in many ways the glue that binds so many scientists from so many different disciplines together in this organization called the LSC. And with the introduction of the upper limits groups with the LSC, LIGO's common mode of coupling these scientists together has become even stronger." -- Kent Blackburn, LIGO-Caltech
"LIGO will 'listen' to the Universe in a spectrum never before 'heard' by humankind. What will we find? We really do not know. Most of the Universe remains a mystery despite the depth of our knowledge. This leaves us with exciting prospects for discovery. But it will not be easy to come by. Building LIGO was an enormous challenge for the LIGO Laboratory, and brining this instrument to the maturity required for science remains a big challenge for the LSC." -- Jim Brau, University of Oregon
"What I like in this experiment is that the research it's aimed to fulfill is purely pleasure of knowledge." -- Erika D'Ambrosio, LIGO-Caltech
"The collaboration between different groups in the U.S. and across continents also shows a different, 'friendlier' way to do experiments, in what I think is a less competitive way than in the other fields with large collaboration. The most challenging aspect is getting the experiment going and waiting (and working) for the results to come." -- Gabriela Gonzalez, Penn State
"The most exciting thing about LIGO is that it represents an extremely rare chance to get actual data on gravity beyond the Newtonian limits. This is the great unexplored realm of physics, and finally entering this realm will almost certainly give us new insights into both physics and astronomy. The challenge, of course, is that the experiment is so difficult. Every aspect of the instrument has to work at close to the quantum noise limit for LIGO to detect something. We need experts in every field that influences LIGO--lasers, vacuum technology, thermal noise, vibration isolation, controls, data analysis, astrophysics, optics, etc." -- Gregg Harry, Syracuse University
"To establish international collaborations, and then an international network of the gravitational wave detectors, is the most exciting as well as the most challenging aspect." -- Seiji Kawamura, NAOJ-TAMA
"LIGO is attempting to make the most precise measurement of distance ever. This is in itself an amazing feat. It will also look for an effect of general relativity, namely the distortion of space time, in real time as it affects the space around us from events that are astrophysically remote." -- Joe Kovalik, LIGO-Livingston Observatory
"The most exciting aspect of the project to me is that we simply don't know what we're going to see. The most challenging part of the project will be attaining design sensitivity across the nominal bandwidth of detection." -- Keith Riles, University of Michigan
"The most exciting aspect of LIGO is that, for the first time, there is enough money dedicated and sufficiently advanced technology to allow the possibility of direct detection of a fundamental aspect of nature: gravity waves. . ." -- Anthony Rizzi, LIGO-Livingston Observatory
"It will be (is) very challenging to keep one's eyes up on the horizon when there is so much action on the road in front of us." -- Rick Savage, LIGO-Hanford Observatory
"We have the opportunity to do something completely new, and it's clear that LIGO should eventually be able to do some important science with gravitational waves. It might turn out to take several more years to really reach its full potential, but we'll get there." -- Peter Shawhan, LIGO-Caltech
These responses represent a flavor of the excitement and anticipation growing among the LIGO Science Collaboration. And it seems clear that the next LSC will continue to serve as a stimulus for striving beyond today's knowledge and reaching for ever greater discoveries and accomplishments!