Our research is based on the technique of pulsar timing, and what we can learn about the Solar System, the Milky Way and the Universe, by observing pulsars at radio frequencies. The following specific research projects form the core of our work:
Gravitational wave detection: We are part of the international effort to make the first direct detection of gravitational waves. The gravitational waves we expect to detect, originate in supermassive binary black holes, which are a necessary consequence of galaxy evolution (according to the standard model). So a positive detection will not only lift the final veil of Einstein's theory of relativity, but will also tell us a lot more about how galaxies form and evolve, and about the role dark matter plays in the Universe.
Low-frequency pulsar observations and the interstellar medium: We use the low-frequency array (LOFAR) to observe pulsars and to measure the dispersion of the pulsed signals, at unprecedented precision. Firstly this allows us to correct for these dispersive delays (which can help the gravitational-wave detection efforts mentioned above). and secondly we can get a very precise view of the densities and turbulence of interstellar gas clouds, which is a useful probe of Galactic dynamics at the smallest scales.
Timing of close and relativistic binary pulsars: The high-precision timing possible today, allows very precise measurements of the binary systems some pulsars inhabit. This the case of double neutron stars, this enables highly precise tests of relativistic gravity and in the case of pulsars in close orbits with semi-degenerate stars, it provides insight into the interior and winds of these stars, which cannot be probed otherwise.
Besides these main topics, we are interested in a variety of pulsar-related research, including pulsar population statistics, single pulse studies, pulsar mass measurements, development of techniques and code for pulsar timing analyses and pulsar timing stability analysis.
- Specific methods of time-frequency metrology
- Short term stability, long term stability
- Fundamental science
- Astronomy, astrophysics (radioastronomy, VLBI, gravitational waves sensors)