8 research outputs found
Characterizing the Directionality of Gravitational Wave Emission from Matter Motions within Core-collapse Supernovae
We analyze the directional dependence of the gravitational wave (GW) emission
from 15 3D neutrino radiation hydrodynamic simulations of core-collapse
supernovae. We develop a new analytic technique to characterize the
distribution of GW emission over all angles. We use physics-informed toy models
to provide closed form expressions for the distribution of GW emission for
different CCSN phases. Using these toy models, we approximate the PNS dynamics
during multiple CCSN stages and obtain similar GW distributions to simulation
outputs. By applying this new technique throughout the supernova duration, we
construct a distribution of preferred directions of GW emission. Our findings
indicate CCSNe do not have a single `optimal' viewing angle along which the
strongest GWs can be detected. For nonrotating cases, this dominant viewing
angle drifts isotropically throughout the supernova, set by the dynamical
timescale of the protoneutron star. For rotating cases, during core bounce and
the following tens of ms, the strongest GW signal is observed along the
equator. During the accretion phase, comparable -- if not stronger -- GW
amplitudes are generated along the axis of rotation, which can be enhanced by
the low T/|W| instability. We show two dominant factors influencing the
directionality of GW emission are the degree of initial rotation and explosion
morphology. Lastly, looking forward, we note the sensitive interplay between GW
detector site and supernova orientation, along with its effect on detecting
individual polarization modes.Comment: 32 pages, 17 Figures, submitted to Ap
Characterizing the Directionality of Gravitational Wave Emission from Matter Motions within Core-collapse Supernovae
We analyze the directional dependence of the gravitational wave (GW) emission from 15 3D neutrino radiation hydrodynamic simulations of core-collapse supernovae (CCSNe). Using spin weighted spherical harmonics, we develop a new analytic technique to quantify the evolution of the distribution of GW emission over all angles. We construct a physics-informed toy model that can be used to approximate GW distributions for general ellipsoid-like systems, and use it to provide closed form expressions for the distribution of GWs for different CCSN phases. Using these toy models, we approximate the protoneutron star (PNS) dynamics during multiple CCSN stages and obtain similar GW distributions to simulation outputs. When considering all viewing angles, we apply this new technique to quantify the evolution of preferred directions of GW emission. For nonrotating cases, this dominant viewing angle drifts isotropically throughout the supernova, set by the dynamical timescale of the PNS. For rotating cases, during core bounce and the following tens of milliseconds, the strongest GW signal is observed along the equator. During the accretion phase, comparable—if not stronger—GW amplitudes are generated along the axis of rotation, which can be enhanced by the low T /∣ W ∣ instability. We show two dominant factors influencing the directionality of GW emission are the degree of initial rotation and explosion morphology. Lastly, looking forward, we note the sensitive interplay between GW detector site and supernova orientation, along with its effect on detecting individual polarization modes