Gravitational physics theory and observations (WG Leader: Ian Jones)

The strong gravitational fields of neutron stars make them potentially detectable sources of gravitational waves, both as members of binary systems, and as individual emitters when they are produced in a core-collapse supernova, when they collapse to a black hole, or undergo any sort of non-spherical oscillation. Indeed, the inspiral and coalescence of neutron star binary systems (either as double neutron star systems or when considering the presence of a black hole) are the prime candidates for the first ever detection of gravitational waves by the LIGO/Virgo detector network. Their discovery would provide an important test of strong-field general relativity, but such detections require accurate signal templates. Most significantly for this Action, the late stages of the coalescence, and the merger itself, will be sensitive to the equation of state of the colliding stars. The construction of sensitive templates, by means of large-scale numerical computations, will be a central task of WG3, and provides an intimate connection between this and WG2. The final merger itself is likely to produce a short GRB. Detailed numerical modelling of this process connects therefore with the activities of WG1, and, through possibly populating the Galaxy with heavy elements, has important repercussions for the nuclear/subnuclear physics explored in WG2. Equally important, individual neutron stars can emit gravitational waves through a variety of mechanisms. These include non-axisymmetries of rotating stars induced by elastic/magnetic strains, and excitation of normal modes of oscillation. Both of these are sensitive to detailed properties of the equation of state and are closely related to the calculations of WG2, while the effect of gravitational-wave emission on neutron star spin frequency provides a natural link with the activities of WG1.
As outlined above, in addition to WGs and their work described above, the research will be catalyzed by three synergy agents. These will be senior scientists with interdisciplinary expertise, who will ensure that a high level of communication is setup among the various WGs and will provide input on possible new synergies.

Topic Leaders in this working group are:

  • Andreas Bauswein
  • Bruno Giacomazzo
  • Leonardo Gualtieri
  • Tanja Hinderer

The annual WG reports can be found here: