paper

The influence of model parameters on the prediction of gravitational wave signals from stellar core collapse

arXiv:1001.1570 · doi:10.1051/0004-6361/200913220

Abstract

We present the gravitational wave (GW) analysis of an extensive series of 3D MHD core-collapse simulations. Our 25 models are launched from a 15 solar mass progenitor, a spherically symmetric effective general relativistic potential, the Lattimer-Swesty or the Shen equation of state (EoS), and a neutrino parametrisation scheme which is accurate until about 5ms postbounce. For 3 representative models, we also include long-term neutrino physics by means of a leakage scheme. Non- or only slowly rotating models show GW emission due to prompt and proto-neutron star convection, allowing the distinction between the two different nuclear EoS. For moderately or fast rotation rates models, we find, in agreement with recent results, only a type I GW signature at core bounce. Models which are set up with an initial central angular velocity of >~ 2pi rad/s emit GWs due to the low T/|W| dynamical instability during the postbounce phase. Weak B-fields do not notably influence the dynamical evolution of the core and thus the GW emission. However, for strong initial poloidal B-fields (~1e12 G),flux-freezing and field winding leads to conditions where P_{mag}/P_{mat} ~ 1, causing the onset of a jet-like supernova explosion and hence the emission of a type IV GW signal. In contradiction to axisymmetric simulations, we find evidence that nonaxisymmetric fluid modes can counteract or even suppress jet formation for models with strong initial toroidal B-fields. We point out that the inclusion of the deleptonisation during the postbounce phase is an indispensable issue for the quantitative prediction of GWs from core-collapse supernovae, as it can alter the GW amplitude up to a factor of 10 compared to a pure hydrodynamical treatment.

23 pages, 25 figures, accepted, to be published in A&A

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