Berlin 2015 – wissenschaftliches Programm
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GR: Fachverband Gravitation und Relativitätstheorie
GR 16: Numerical Relativity
GR 16.6: Vortrag
Donnerstag, 19. März 2015, 17:10–17:30, H 2013
Initial data for binary neutron stars with adjustable eccentricity — •Niclas Moldenhauer1, Charalampos Markakis2, Nathan Johnson-McDaniel3, Wolfgang Tichy4, and Bernd Brügmann1 — 1Theoretical Physics Institute, University of Jena — 2Mathematical Sciences, University of Southampton — 3ICTS of the Tata Institute of Fundamental Research — 4Physics Department, Florida Atlantic University,
Binary neutron stars in circular orbits can be modeled as helically symmetric, i.e., stationary in a rotating frame. This symmetry gives rise to a first integral of the Euler equation. For eccentric orbits, however, the lack of helical symmetry has prevented the use of this method, and the numerical relativity community has often resorted to constructing initial data by superimposing boosted spherical stars, which leads to spuriously excited neutron star oscillations during the evolution. We consider eccentric confgurations at apoapsis that are instantaneously stationary in a rotating frame and extend the notion of helical symmetry to eccentric orbits. We use the obtained first integrals as the basis of a self-consistent iteration of the Einstein constraints to construct conformal thin-sandwich initial data for eccentric binaries. We discuss that effect of the improved data on the evolutions, e.g. by looking at the spurious stellar oscillations and the tidally induced oscillations.