The LISA Symposia occur every two years, with the location alternating between Europe and the U.S. The LISA Symposium was held this year in Barcelona, Spain from the July. The Symposium was jointly organized by the Institute of Space Sciences (ICE) [National Spanish Research Council (CSIC) & Institut of Space Studies of Catalonia (IEEC)], and the local organizing committee was the LISA group led by Alberto Lobo. The venue for this year was the excellent science museum CosmoCaixa. The Symposium was sponsored by the European Space Agency, the Albert Einstein Institute, the La Caixa Foundation, the Spanish Ministry of Science and Education (MEC), the Catalan Agency for Research and University Funding (AGAUR), the National Spanish Research Council, the Spanish Society of Gravitation and Relativity (SEGRE), the University of Barcelona (UB), the Polytechnic University of Catalonia (UPC), and the Institute for High Energy Physics (IFAE).
Each day started with a number of plenary lectures, splitting off into parallel sessions in the afternoons. While the status of LISA has been enjoying a bit of a rollercoaster ride in the last few years, it was nice to see that the number of people working on LISA and LISA Pathfinder continues to grow. This year's Symposium had 226 registered participants. There were 30 plenary lectures, 78 parallel session presentations and 75 poster contributions. The lists of speakers and sessions can be found on-line at
On the Wednesday of the meeting, there was an outreach lecture by Prof. Clifford Will entitled ``Black holes, waves of gravity and other warped ideas of Dr Einstein.''
The plenary talks covered a large area this year. On the first day we heard about how LISA is fitting into both ESA's Cosmic Vision Plan for 2015-2025 and NASA's Physics of the Cosmos theme. There were a number of talks about LISA and LISA Path Finder (LPF) technology, engineering advances for both projects, data analysis for LPF and the question of optimal mission size and duration. In the weeks leading up to the Symposium, there had been a call from NASA to investigate mission downsizing for LISA. The outcome of this investigation was that there would be a large loss of science for a small saving of money. Therefore, it looks like the proposed mission is the optimal mission. There was also a presentation about the status of the ground based detectors. Other talks covered topics such as advances in data analysis for LISA and the growing link between data analysts and astrophysicists. One highlight of the meeting was the advance in numerical simulations and numerical relativity. We were treated to some very interesting presentations on structure formation at galactic centers and the numerical modelling of inspiral waveforms, through merger and into the ringdown phase. One of the other motivating aspects is the advance in data analysis techniques since the last LISA Symposium. We are now starting to investigate more difficult sources such as spinning black hole binaries, extreme mass ratio inspirals (EMRIs) and more realistic galaxy models.
The parallel sessions for LISA/LPF had a heavy emphasis on technology for LPF due to the rapidly approaching launch date. One of the main topics of discussion was LPF data analysis and the types of science that could be done with LPF. There were also presentations on the LISA Technology Package (LTP). The goal of this experiment is to investigate the sources of disturbances that may cause the test masses to be perturbed from geodesic trajectories. There is work being done on the development of a data analysis algorithm, and there was also the announcement of the first LTP Mock Data Challenge. Finally, there were presentations on other detectors such as DECIGO, Super-Astrod and GRACE, and how technology from both LISA and LPF could be used to enhance these missions.
The theory parallel sessions could normally be divided into three distinct areas : data analysis, astrophysics and numerical relativity. One of the most uplifting aspects of this particular meeting was seeing that the divisions between the areas has really started to become blurred. Groups from all three areas are now communicating and working with each other to develop search algorithms based on more realistic initial data and waveforms. The main areas of interest for a lot of the presentations were the inspirals of massive black holes and EMRIs. These focused on more realistic EMRI waveforms, binary inspirals with higher harmonic corrections, spin, eccentricity and numerical mergers. There were also discussions on the detection of Intermediate Mass Binaries, the possibility of detecting cosmic superstrings and constraining both string theory and dark energy predictions with LISA.
The Proceedings of the Symposium will be published jointly by Classical and Quantum Gravity and the Journal of Physics: Conference Series of the Institute of Physics (IoP).
From the level of participation, and the advances that have been made since the last LISA Symposium, the community is looking very healthy and is on track for both the launches of LPF and LISA.