SMuK 2023 – scientific programme
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GR: Fachverband Gravitation und Relativitätstheorie
GR 1: Black Holes
GR 1.3: Talk
Monday, March 20, 2023, 17:10–17:30, ZEU/0260
Formulation Improvements for Critical Collapse Simulations — •Daniela Cors1, Sarah Renkhoff1, Hannes Rüter2, David Hilditch3, and Bernd Brügmann1 — 1Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universität Jena — 2CFisUC, Department of Physics, University of Coimbra — 3CENTRA, Instituto Superior Técnico, University of Lisbon
We use our adapted pseudospectral code bamps, with its new hp adaptive mesh refinement, to tune close to the barrier between gravitational collapse and dispersed fields, in order to study the critical phenomena that emerges near that threshold. To achieve that goal and improve our previous results, we introduce adjustments to the generalised harmonic gauge formulation of General Relativity adapting it to the specific case of near collapse simulations. In particular, we adjust the constraint violations damping scheme, taking into account the collapse of the lapse that occurs in extreme spacetimes. We also prevent coordinate singularities by carefully choosing the gauge source function for collapsing spacetimes. As a result of these changes, we manage to improve our threshold estimation results. In spherical symmetry, we show critical phenomena of a massless scalar field minimally coupled to the Einstein field equations. In axisymmetry, we study gravitational waves in vacuum, revisiting our previous results.