3 research outputs found
Measuring the Angular Momentum Distribution in Core-Collapse Supernova Progenitors with Gravitational Waves
The late collapse, core bounce, and the early postbounce phase of rotating
core collapse leads to a characteristic gravitational wave (GW) signal. The
precise shape of the signal is governed by the interplay of gravity, rotation,
nuclear equation of state (EOS), and electron capture during collapse. We
explore the dependence of the signal on total angular momentum and its
distribution in the progenitor core by means of a large set of axisymmetric
general-relativistic core collapse simulations in which we vary the initial
angular momentum distribution in the core. Our simulations include a
microphysical finite-temperature EOS, an approximate electron capture treatment
during collapse, and a neutrino leakage scheme for the postbounce evolution. We
find that the precise distribution of angular momentum is relevant only for
very rapidly rotating cores with T/|W|>~8% at bounce. We construct a numerical
template bank from our baseline set of simulations, and carry out additional
simulations to generate trial waveforms for injection into simulated advanced
LIGO noise at a fiducial galactic distance of 10 kpc. Using matched filtering,
we show that for an optimally-oriented source and Gaussian noise, advanced
Advanced LIGO could measure the total angular momentum to within ~20%, for
rapidly rotating cores. For most waveforms, the nearest known degree of
precollapse differential rotation is correctly inferred by both our matched
filtering analysis and an alternative Bayesian model selection approach. We
test our results for robustness against systematic uncertainties by injecting
waveforms from simulations using a different EOS and and variations in the
electron fraction in the inner core. The results of these tests show that these
uncertainties significantly reduce the accuracy with which the total angular
momentum and its precollapse distribution can be inferred from observations.Comment: 22 pages, 16 figure