Gravitational wave signatures ofab initiotwo-dimensional core collapse supernova explosion models for12–25  M⊙stars

Abstract

We present the gravitational waveforms computed in ab initio two-dimensional core collapse supernova models evolved with the Chimera code for progenitor masses between 12 and 25 M . All models employ multi-frequency neutrino transport in the ray-by-ray approximation, state-of-the-art weak interaction physics, relativistic transport corrections such as the gravitational redshift of neutrinos, two-dimensional hydrodynamics with the commensurate relativistic corrections, Newtonian self-gravity with a general relativistic monopole correction, and the Lattimer-Swesty equation of state with 220 MeV compressibility, and begin with the most recent Woosley-Heger nonrotating progenitors in this mass range. All of our models exhibit robust explosions. Therefore, our waveforms capture all stages of supernova development: 1) a relatively short and weak prompt signal, 2) a quiescent stage, 3) a strong signal due to convection and SASI activity, 4) termination of active accretion onto the proto-neutron star, and 5) a slowly increasing tail that reaches a saturation value. Fourier decomposition shows that the gravitational wave signals we predict should be observable by AdvLIGO for Galactic events across the range of progenitors considered here. The fundamental limitation of these models is in their imposition of axisymmetry. Further progress will require counterpart three-dimensional models, which are underway.

A New Gravitational-Wave Signature From Standing Accretion Shock Instability in Supernovae

“…The characteristic GW frequency is considered as a result of the g-mode oscillation excited by the downflows to the PNS ) and by the deceleration of convection plumes hitting the surface (Murphy et al 2009). These features have also been identified in more recent 2D models with the best available neutrino transport scheme (Yakunin et al 2010;Müller et al 2013;Yakunin et al 2015). Furthermore, Müller et al (2013) showed in their self-consistent 2D models that the SASI motions become generally more violent for more massive progenitors, which tends to make the GW amplitudes and frequencies higher.…”

Observing gravitational waves from core-collapse supernovae in the advanced detector era

“…The GW signal from these convective processes has a broad spectrum. The prompt convection GW emission occurs at frequencies in the range 100-300 Hz, while neutrino-driven convection at later times sources GW emission with significant power at frequencies between ∼300-a1000 Hz (increasing with time [12][13][14][15]). Proto-NS convection contributes at the highest frequencies (≳1000 Hz).…”

“…It is more relevant, astrophysically to consider the corresponding 50% upper limit on the energy emitted in GWs, E 50% GW , which we compute from h 50% rss using Eq. (15). After the on-source data has been analyzed and S max on computed, we inject a large number of known signal events for families of waveforms for which h 50% rss and d 50% (where applicable) are desired.…”

“…They potentially carry information not only on the general degree of asymmetry in the dynamics of the CCSN, but also more directly on the explosion mechanism [1,10,11], on the structural and compositional evolution of the protoneutron star [12][13][14][15], the rotation rate of the collapsed core [16][17][18][19], and the nuclear equation of state [17,20,21].…”

Probing mass-radius relation of protoneutron stars from gravitational-wave asteroseismology

“…Extensive numerical simulations have been done so far to study GW signatures from core-collapse supernovae (e.g., [10][11][12][13][14][15][16]). It is now almost certain that the g-mode oscillations excited in the vicinity of the protoneutron star (PNS) are one of the most strong GW emission processes in the postbounce supernova core.…”