MoGEs · Modelling of Generic Extreme mass-ratio inspirals

Modelling of Generic Extreme mass-ratio inspirals

The detection of gravitation waves (GWs) has opened up a new avenue for learning about the universe an its contents. Observable GWs primarily originate from the distant mergers of compact objects such as black holes or neutron stars. Current GW observing facilities (LIGO and Virgo) are sensitive mostly mergers of objects with similar masses. Future facilities --- such as ESA's space-based GW observatory, LISA, and the next generation of ground-based observatories, Einstein Telescope and Cosmic Explorer --- will be sensitive to the mergers of compact objects with greatly different masses. One class of such mergers are called Extrene Mass Ratio Inspirals or EMRIs. EMRIs consist of a compact object between 1 and 50 times as massive as the sun mergering with a supermassive black hole in the center of a galaxy. Detection of one such an event with LISA will allow us to determine many of the properties of the host supermassive black hole to exquist detail shining light on many of the mysteries that surround these behemoths and the star clusters that surround them, as well as sensitively probe Nature for deviations from our current best theory of gravity, Einstein's General Relativity. EMRIs are detectable at great distances, billions of lightyears away. By detecting many we can map out the accelerated expansion of the universe independently from observations using electromagnetic waves such as light. This will help shed light on the mysteries of dark energy and matter. The detection and analysis of GW signals requires accurate theoretical models of the source systems. The scientific community has been very successful in modelling compact binary mergers with similar masses, such as detected by LIGO and Virgo. Systems with very small mass-ratios, such as EMRIs, however are well beyond the reach for current modelling methods. The MoGEs project aims to improve the modelling of small mass-ratio binaries using the Gravitation Self-Force (GSF) formalism which describes the motion of the object as an perturbative series in the mass-ratio. The main objectives of the MoGEs project was tackling longstanding problems surrounding applying the GSF formalism to rotating black holes, and using the obtained results to improve the highly successful "Effective One-body" model for compact mergers currently used by LIGO and Virgo.

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