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Proposing Institution

Institut für Astrophysik , Astrophysikalische Kosmologie, Göttingen University Germany
Project Manager

Dr. Katy Clough
Friedrich-Hund-Platz 1
37077 Göttingen
Despite the success of general relativity (GR), many questions concerning the nature of gravity remain unanswered at cosmological and high-energy scales. For example, explaining the early evolution of our universe during inflation or identifying the constituents of dark matter (DM). A new era of “gravitational astronomy” has opened with the recent direct detection of gravitational waves (GWs). This offers a unique opportunity to investigate and probe gravity in its most extreme, non-linear, dynamical regime.In order to make full use of the observations, it is crucial to understand the strong-field dynamics and the gravitational radiation produced. This is because searching for signals with GW observatories like LISA heavily relies on the existence of a-priori known waveform templates, without which the signals may go unnoticed. However, little is known about the expected GW emission during inflation or during the merger of two BHs in the presence of dark matter candidates, like light scalar axion fields. Such investigations go beyond analytic calculations in symmetric spacetimes, and thus necessitate large simulations with established Numerical Relativity (NR) codes.In our research we wish to address two key issues. Firstly, exploring the interplay between BHs and DM candidates represented by light fundamental fields and the resulting GW signals. We also wish to identify the behaviours and signatures imprinted during inhomogeneous inflation and the subsequent reheating period. We use the NR code GRChombo, see www.grchombo.org, which is written to take full advantage of modern parallel computing techniques. GRChombo's features include full adaptive mesh refinement (AMR) with block structured Berger-Rigoutsos grid generation, and massive parallelism through the Message Passing Interface (MPI). GRChombo evolves the Einstein equation with the standard BSSN formalism, with an option to turn on CCZ4 constraint damping if required.

Impressum, Conny Wendler