Characteristic time variability of gravitational-wave and neutrino signals from three-dimensional simulations of non-rotating and rapidly rotating stellar core collapse

Abstract

We present results from full general relativistic three-dimensional hydrodynamics simulations of stellar core collapse of a 70 M⊙ star with spectral neutrino transport. To investigate the impact of rotation on non-axisymmetric instabilities, we compute three models by parametrically changing the initial strength of rotation. The most rapidly rotating model exhibits a transient development of the low-T/|W| instability with one-armed spiral flow at the early postbounce phase. Subsequently, the two-armed spiral flow appears, which persists during the simulation time. The moderately rotating model also shows the growth of the low-T/|W| instability, but only with the two-armed spiral flow. In the nonrotating model, a vigorous activity of the standing accretion-shock instability (SASI) is only observed. The SASI is first dominated by the sloshing mode, which is followed by the spiral SASI until the black hole formation. We present a spectrogram analysis of the gravitational waves (GWs) and neutrinos, focusing on the time correlation. Our results show that characteristic time modulations in the GW and neutrino signals can be linked to the growth of the non-axisymmetric instabilities. We find that the degree of the protoneutron star (PNS) deformation, depending upon which modes of the non-axisymmetric instabilities develop, predominantly affects the characteristic frequencies of the correlated GW and neutrino signals. We point out that these signals would be simultaneously detectable by the current-generation detectors up to ∼10 kpc. Our findings suggest that the joint observation of GWs and neutrinos is indispensable for extracting information on the PNS evolution preceding the black hole formation.

Pulsational pair-instability supernovae: gravitational collapse, black-hole formation, and beyond

“…Our GW signals exhibit all of the well known features found in most other modern 2D and 3D CCSN simulations published over the past two decades (e.g., Müller et al 2004;Murphy et al 2009;Müller et al 2013;Cerdá-Durán et al 2013;Yakunin et al 2015;Kuroda et al 2016;Kuroda et al 2017;Morozova et al 2018;Radice et al 2019;Mezzacappa et al 2020;Shibagaki et al 2021;Pan et al 2018Pan et al , 2021Andresen et al 2017Andresen et al , 2019Andresen et al , 2021Powell & Müller 2019;Powell et al 2021;Jardine et al 2021). In the following we compare some 16)) is performed.…”

Universal relation for supernova gravitational waves

“…The gravitational waves from supernova explosions have been mainly studies via numerical simulations (e.g., [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]). These simulations tell us the existence of the gravitational wave signals, whose frequency increases from a few hundred hertz up to a few kilohertz in ∼ 1 second after corebounce.…”

Application of the Hilbert-Huang transform for analyzing standing-accretion-shock-instability induced gravitational waves in a core-collapse supernova

“…The time modulated mass accretion penetrates deep into the PNS and trigger a surface distortion and motion of the central PNS core. From there and also from the globally deformed regions behind the shock [29], sizeable GWs could be emitted with their time frequency being characterized by the SASI frequency of the order of ∼ 100 Hz [29][30][31][32][33][34][35][36] (we call them as SASI mode here after).…”