PreciseEMRIs · Precise predictions for extreme mass ratio inspirals

Precise predictions for extreme mass ratio inspirals

The gravitational-wave sky was opened in the past few years by the first measurement of binary black-hole inspirals by the terrestrial gravitational-wave detectors LIGO, Virgo and KAGRA. A new chapter of this story is in the making as the European space agency approved a completely new type of detector of gravitational waves in 2017, the space-based Laser interferometer space antenna (LISA), as one of its three highest-priority missions for the 2030s. The scientific capabilities of LISA provide European science with a chance to be at the absolute cutting edge of gravitational-wave astronomy, to "see" new extreme phenomena in the Universe, and to deepen our understanding of Nature. The sensitivity of LISA will be in the in the millihertz gravitational-wave band and it will observe new types of phenomena not seen by the terrestrial detectors. One of the most prominent and interesting sources seen in this band are the so-called extreme mass ratio inspirals (EMRIs), where a comparatively light, stellar-mass compact object spirals into a super-massive black hole. However, at the moment the precise predictions for the evolution of EMRIs are not ready, and this, if not rectified, would imply lower yields of valuable science to be obtained from the LISA mission. The subject of this project was to contribute to the development of these precise predictions, and to prepare for the discovery of new fundamental science with LISA and other gravitational-wave detectors. In particular, the overall objectives of the project were (1) to develop theoretical and mathematical tools to incorporate various new corrections to the evolution of EMRIs and gravitational-wave inspirals in general, (2) to synergize these existing frameworks with previous models used for gravitational-wave inspirals, (3) to describe and incorporate various astrophysical effects on the inspirals such as the effect of plasma swirling in the environment, or the gravity of the surrounding galaxy, and (4) to delve deep into the mathematical equations describing the problem and try to find various tricks to deal with them more efficiently and accurately. Even though the launch of LISA is more than 10 years in the future, the mathematical and technical challenge of providing the precise predictions is extremely non-trivial, and intense work must thus be initiated now. This research project not only contributed a significant part of the work needed, but it also allowed the Researcher to acquire the necessary skill and network to become an established scientist in the field of gravitational-wave theory that will be able to carry on in this ambitious research programme.

Data: CORDIS, © European Union