Gravitational wave burst signal from core collapse of rotating stars
We present results from detailed general relativistic simulations of stellar core collapse to a proto-neutron star, using two different microphysical nonzero-temperature nuclear equations of state as well as an approximate description of deleptonization during the collapse phase. Investigating a wide variety of rotation rates and profiles as well as masses of the progenitor stars and both equations of state, we confirm in this very general setup the recent finding that a generic gravitational wave burst signal is associated with core bounce, already known as type I in the literature. The previously suggested type II (or "multiple-bounce") waveform morphology does not occur. Despite this reduction to a single waveform type, we demonstrate that it is still possible to constrain the progenitor and postbounce rotation based on a combination of the maximum signal amplitude and the peak frequency of the emitted gravitational wave burst. Our models include to sufficient accuracy the currently known necessary physics for the collapse and bounce phase of core-collapse supernovae, yielding accurate and reliable gravitational wave signal templates for gravitational wave data analysis. In addition, we assess the possibility of nonaxisymmetric instabilities in rotating nascent proto-neutron stars. We find strong evidence that in an iron core-collapse event the postbounce core cannot reach sufficiently rapid rotation to become subject to a classical bar-mode instability. However, many of our postbounce core models exhibit sufficiently rapid and differential rotation to become subject to the recently discovered dynamical instability at low rotation rates.
Additional Information©2008 The American Physical Society. (Received 30 June 2008; published 19 September 2008) It is a pleasure to thank Shizuka Akiyama, David Arnett, Adam Burrows, Luc Dessart, Pablo Cerdá-Durán, Ian Hawke, Alex Heger, Ewald Mu¨ller, Shangli Ou, José Pons, Erik Schnetter, Ed Seidel, Bernard Schutz, Todd Thompson, Joel Tohline, and Burkhard Zink for helpful comments and inspiring discussions. This work was supported by the Deutsche Forschungsgemeinschaft through the Transregional Collaborative Research Centers Contract No. SFB/TR 27 "Neutrinos and Beyond," Contract No. SFB/TR 7 "Gravitational Wave Astronomy," and the Cluster of Excellence EXC 153 "Origin and Structure of the Universe" , by the DAAD and IKY (IKYDA German–Greek research travel grant), and by the European Network of Theoretical Astroparticle Physics Contract No. ENTApP ILIAS/N6 under Contract No. RII3-CT-2004-506222. H.D is supported by a Marie Curie Intra-European Fellowship within the 6th European Community Framework Programme under Contract No. IEF 040464, and C.D.O. by the Joint Institute for Nuclear Astrophysics (JINA) under NSF Sub-Award No. 61-5292UA of NFS Award No. 86-6004791. The authors wish to thank the Max Planck Institute for Gravitational Physics and the John von Neumann-Institut für Computing (NIC) in Jülich where the calculations presented in this paper were performed.
Published - DIMprd08.pdf