Equation of State Dependent Dynamics and Multimessenger Signals from Stellar-mass Black Hole Formation

TL;DR

This study explores how different equations of state influence black hole formation, gravitational wave signals, and neutrino emissions in core-collapse supernovae of a 40 solar mass star, highlighting the importance of EoS in astrophysical signals.

Contribution

It provides the first detailed analysis of EoS-dependent dynamics and multimessenger signals from stellar-mass black hole formation using self-consistent simulations.

Findings

BH formation time varies with EoS from 460 to >1300 ms

Multiple dimensions delay BH formation by 100-250 ms

GW signals include low-frequency bounce, PNS oscillations, and high-frequency convection signals

Abstract

We investigate axisymmetric black hole~(BH) formation and its gravitational wave (GW) and neutrino signals with self-consistent core-collapse supernova simulations of a non-rotating $40~M_\odot$ progenitor star using the isotropic diffusion source approximation for the neutrino transport and a modified gravitational potential for general relativistic effects. We consider four different neutron star (NS) equations of state~(EoS): LS220, SFHo, BHB$\Lambda\phi$ and DD2, and study the impact of the EoS on BH formation dynamics and GW emission. We find that the BH formation time is sensitive to the EoS from 460 to $>1300$~ms and is delayed in multiple dimensions for $\sim~100-250$~ms due to the finite entropy effects. Depending on the EoS, our simulations show the possibility that shock revival can occur along with the collapse of the proto-neutron star~(PNS) to a BH. The gravitational waveforms contain four major features that are similar to previous studies but show extreme values: (1)~a low frequency signal ($\sim~300-500$~Hz) from core-bounce and prompt convection, (2)~a strong signal from the PNS g-mode oscillation among other features, (3)~a high frequency signal from the PNS inner-core convection, and (4)~signals from the standing accretion shock instability and convection. The peak frequency at the onset of BH formation reaches to $\sim~2.3$~kHz. The characteristic amplitude of a 10~kpc object at peak frequency is detectable but close to the noise threshold of the Advanced~LIGO and KAGRA, suggesting that the next generation gravitational wave detector will need to improve the sensitivity at the kHz domain to better observe stellar-mass BH formation from core-collapse supernovae or failed supernovae.