Quasinormal modes of compact astrophysical objects contain much information about the internal structure of such objects and are in this sense like a fingerprint. Therefore a measurement of quasinormal modes could be an interesting problem for future gravitational wave astronomy. This would provide an important way to learn something about the internal structure of, e.g., neutron stars. In this research project resonances between quasinormal modes and orbital motion in an inspiralling binary shall be considered. This is a special case how quasinormal modes can be excited in an astrophysically very realistic situation. Inspiralling compact binaries consisting of black holes and/or neutron stars are expected to be observed by future gravitational wave astronomy on a regular basis. An important question is how accurate the measurements of upcoming generation of gravitational wave detectors must be to make statements about quasinormal modes of neutron stars in this special case. This research project shall provide the foundation to answer this question by deriving an analytic framework to describe the mentioned resonance in general relativity.
Resonances between quasinormal modes and orbital motion as well as their impact on gravitational waveforms have been considered already in the past. However, it was pointed out recently that including general relativistic effects can substantially change the result. The important aspect of this research project is that it aims at a manifestly covariant (though in some respect only approximate) analytic description of such resonances, thus providing a general relativistic framework for this effect.
This research was funded through DFG project STE 2017/1-1 (and STE 2017/2-1) “Resonances of quasinormal modes and orbital motion in general relativistic compact binaries.”