Diagnostics Package and the DMU
The Barcelona contribution to LISA will be based in part on their contribution to LISA Pathfinder (LPF). This consisted of the Diagnostics Package and the DMU. The former is a set of extremely high sensitivity temperature sensors and magnetometers, plus their electronics and calibration hardware, and the Radiation Monitor, a charged particle counter and spectrometer. The DMU (Data Management Unit) is the LISA Pathfinder's payload computer, which interfaces with the main On-Board computer for most telemetry and telecommands related to the payload functions. Barcelona is also heavily involved in the LISA PathFinder mission operations.
The Barcelona Gravitational Wave Astronomy/LISA group is also making an important effort in the description of the main sources of gravitational waves in order to produce gravitational-wave template banks which the detectors need to use for detection and source characterization. The group also does research in gravitational physics oriented to the exploitation of the future gravitational wave observations.
There are various main fronts where this is approached:
- Simulations of Massive Black Hole Mergers
These systems will produce the strongest signals for LISA with signal-to-noise ratios of the order of 100-10000. Detections of such sources will be used to constraint galaxy formation models, study the acceleration of the Universe, understand the structure of black holes, tests of gravity, etc. For the inspiral part of the signal, post-Newtonian methods should be enough, but from the pre-merger phase to the plunge of the system we need to solve the full Einstein equations, and this can only be done numerically and using supercomputers. Our group has one of the few numerical codes available to produce such simulations.
- Simulations and description of Extreme-Mass-Ratio Inspirals (EMRIs)
Another very important source for LISA is the capture and subsequent slow inspiral of a stellar compact object (white dwarf, neutron star, stellar black hole) by a supermassive black hole sitting at a galactic center. During the last year before plunge, these systems will emit hundreds of thousands of gravitational wave cycles inside the LISA band, which will allow for very precise parameter estimation. Using EMRI observations we can learn about the stellar dynamics in galactic centres, distribution of masses and spins of stellar black holes, the "no-hair" conjecture, the viability of alternative theories of gravity, etc. The waveforms of these systems are very long and complex, which is a challenge for the theory.
- Scientific impact of LISA observations
Here we address different possible scenarios in Astrophysics and Cosmology that can produce GWs within the LISA sensitivity band, and to perform statistical analysis of the ability of the instrument to detect them, to extract the characteristic parameters, and its potential scientific impact. We are developing the appropriate tools for using LISA observations of binary black hole mergers and EMRI to test the geometry of black holes (determining their gravitational multipole moments), and alternative theories of gravity.
- Data Analysis tools for the LISA mission
The Barcelona Group is also working in the development of Data Analysis tools for the LISA mission. In particular, in the development of algorithms for the detection and extraction of physical parameters of astrophysical/cosmological sources of gravitational waves for LISA. The LISA Pathfinder experience in the analysis of real data will be used as one of the important pillars for these tasks.