Fifth LISA Symposium

Curt Cutler, Albert Einstein Institute
LISA Symposia are held every two years, with the venue alternating between the U.S. and Europe. The latest one--the Fifth International LISA Symposium--was held at ESTEC (The Netherlands) on July 12-15, 2004. Oliver Jennrich was the main organizer, and it was attended by about 180 scientists.

About 80 talks and almost 30 posters were presented over the course of this 4-day meeting. Almost all the talks are now available on-line at The Proceedings will be published in a special issue of Classical and Quantum Gravity.

The first day was devoted to LISA Pathfinder, a technology demonstrator mission that will test key LISA technologies, especially the inertial sensing and and drag-free control. Also, several different kinds of thrusters (FEEPS, colloidal thusters, cold gas) will be employed, to help determine the best choice for LISA. LISA Pathfinder will carry two instruments: the European LISA Test Package (LTP) and the U.S. Disturbance Reduction System (DRS). Work on both sides of the Atlantic appears to be proceeding smoothly towards LISA Pathfinder's scheduled launch in 2008.

Tuesday morning was devoted to status reviews from the major ground-based detectors (both bars and interferometers). The rest of the meeting was then devoted to sessions on LISA instrumental work, astrophysical sources, modeling and simulation, and LISA data analysis.

The instrumental talks described significant progress on many fronts, including the interferometry, test-mass charging and discharging, self-gravity gradients, and the thrusters. The theoretical talks mainly dealt with coalescences of massive ( $\sim 10^6 M_{\odot})$ black holes, inspirals of stellar-mass compact objects into massive black holes (including the radiation reaction problem), and the problem of ``fitting out'' as many short-period galactic binaries as possible (important since confusion noise from these binaries will actually dominate LISA's noise curve in the low-to-mid-frequency range).

From the sessions on simulations and data analysis, a couple talks were essentially advertisements for new LISA-related websites. I'm happy to use this space to help propagate that information. M. Vallisneri and J. Armstrong have developed a software package called Synthetic LISA for generating synthetic LISA time series, i.e., for computing the TDI responses to gravitational waves and for adding noise with the predicted spectrum. This is available at A similar package called The LISA Simulator has been built by N. Cornish, L. Rubbo, and O. Poujade; it is available at Another relatively new site is the Mock LISA Data Archive (, which contains a collection of simulated data for different source classes, to be used in developing and benchmarking data analysis algorithms.

I'll conclude by mentioning that the Symposium took place under a bit of a cloud, politically. U.S. President Bush's new Vision for NASA (announced in Jan.'04) involves a re-prioritization of NASA activities, with more emphasis on manned missions (leading eventually to astronauts on Mars) and less on space science. To help free up money for the manned program, the budget for the Beyond Einstein program was cut back significantly: the LISA schedule was delayed by one year, Constellation-X was delayed two years, and the Einstein Probes (like the Dark Energy Probe) were eliminated from the budget completely. However, despite these developments, knowledgeable insiders generally opined that LISA enjoys sufficient support, both from Congress and within NASA, that further budget tightening for science would probably just lead to further delays, as opposed to LISA's cancellation.

Jorge Pullin 2004-09-10