Christian D. Ott
CQG 26, 063001 (2009)
- Gravitational Wave Signature Data -
Abstract
| We review the ensemble of anticipated gravitational-wave (GW) emission processes in stellar core collapse and postbounce core-collapse supernova evolution. We discuss recent progress in the modeling of these processes and summarize most recent GW signal estimates. In addition, we present new results on the GW emission from postbounce convective overturn and protoneutron star g-mode pulsations based on axisymmetric radiation-hydrodynamic calculations. Galactic core-collapse supernovae are very rare events, but within 3 5 Mpc from Earth, the rate jumps to 1 in ~2 years. Using the set of currently available theoretical gravitational waveforms, we compute upper-limit optimal signal-to-noise ratios based on current and advanced LIGO/GEO600/VIRGO noise curves for the recent SN 2008bk which exploded at ~3.9 Mpc. While initial LIGOs cannot detect GWs emitted by core-collapse events at such a distance, we find that advanced LIGO-class detectors could put significant upper limits on the GW emission strength for such events. We study the potential occurrence of the various GW emission processes in particular supernova explosion scenarios and argue that the GW signatures of neutrino-driven, magneto-rotational, and acoustically-driven core-collapse SNe may be mutually exclusive. We suggest that even initial LIGOs could distinguish these explosion mechanisms based on the detection (or non-detection) of GWs from a galactic core-collapse supernova. |
Gravitational Waves from Convection and the Standing Accretion Shock Instability (SASI)
In section 6 of the review article, we discuss the gravitational-wave emission from convective overturn and the standing-accretion-shock instability (SASI). The new results are based on two supernova simulations run with the code VULCAN/2D and using the 15-solar-mass presupernova model from Woosley & Weaver (1995). Model s15WW95 is the baseline model run with standard resolution (see Burrows et al. (2007) for details) while model s15WW95HR was run with 45% more zones inside 300 km from the origin to study the effect of resolution on the turbulent fluid dynamics and the resulting gravitational-wave signal. More details can be found in the article.
Here we provide GW signal data from models s15WW95 and s15WW95HR. The signal was extracted from the fluid motions via the quadrupole approximation which trivially allows one to highlight certain emission regions by excluding others. This proves useful when trying to isolate emission regions and processes. Due to the assumed axisymmetry, there is only one polarization (h_+ if the symmetry axis is the z axis) and the waveforms are given for a distance of 10 kpc as seen by an equatorial observer.
| GW signal data | ||
| GWs from prompt postbounce convection. The emission sets in immediately after core bounce and lasts for 20-30 ms. It is strongest in regions within ~50-70 km of the origin. | s15WW95 | s15WW95HR |
| GWs from neutrino-driven convection and SASI in the postshock region above ~60 km. These waveforms were computed by cutting out the inner ~60 km of the grid. The bounce part of the waveform (prompt convection) is cut out. | s15WW95 | s15WW95HR |
| Full waveforms without radial cuts and including prompt convection, PNS convection, neutrino-driven convection and SASI as well as the onset of PNS core pulsations. | s15WW95 | s15WW95HR |
Gravitational Waves from Protoneutron Star Pulsations in the Context of the Acoustic Mechanism of Core-Collapse Supernovae
Below we provide gravitational wave signature data for models whose radiation-hydrodynamic evolutions were discussed in Burrows et al., "Features of the Acoustic Mechanism of Core-Collapse Supernova Explosions," ApJ 655, 416 (2007). Here we present the gravitational wave data from calculations that made use of the nonrotating 11.2, 13.0, 15.0, 20.0, and 25.0 Msun presupernova models of [Woosley et al. 2002 (WHW02)] (models with prefix "s") and of the nonrotating 13 and 15 Msun progenitors of [Nomoto & Hashimoto 1988] (models with prefix "nomoto"). For each model we provide the axisymmetric mass-quadrupole gravitational wave strain as observed at 10 kpc distance by an observer located on the equator. All files are gzipped plain text ASCII. The gravitational wave emission associated with anisotropic neutrino radiation fields was not computed. A summary table can be found in Ott 2009
Download tar-ball including gravitational wave data of all models. |
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| Model | |||||||
| s11.2 | s13.0 | s15.0 | s20.0 | s25.0 | nomoto13 | nomoto15 | |
| Mass-quadrupole h+ time (s), h+ scaled to 10 kpc distance. |
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