Unveiling the central engine of core-collapse supernovae in the Local Universe: NS or BH?

TL;DR

This paper explores how gravitational wave observations can distinguish whether core-collapse supernovae in the local universe are powered by neutron stars or black holes, based on their energy signatures and event rates.

Contribution

It provides a detailed analysis of gravitational wave signatures from black hole and neutron star engines in supernovae, proposing GW calorimetry as a method to identify the central engine type.

Findings

GW signals can differentiate NS and BH engines in supernovae.

Predicted GW energy and frequency ranges for BH central engines.

Event rates within 50-100 Mpc could enable this distinction.

Abstract

The physical trigger powering supernovae following the core collapse of massive stars is believed to involve a neutron star (NS) or a black hole (BH), depending largely on progenitor mass. A potentially distinct signature is a long-duration gravitational wave (GW) burst from BH central engines by their ample energy reservoir $E_J$ in angular momentum, far more so than an NS can provide. A natural catalyst for this radiation is surrounding high-density matter in the form of a non-axisymmetric disk or torus. Here, we derive a detailed outlook on LVK probes of core-collapse supernovae CC-SNe during the present observational run O4 based on their event rate, an association with normal long GRBs and mass-scaling of GW170817B/GRB170817A. For BH central engines of mass $M$, GW170817B predicts a descending GW-chirp of energy ${\cal E}_{GW}\simeq 3.5\% M_\odot c^2 \left(M/M_0\right)$ at frequency $f_{GW}\lesssim 700\,{\rm Hz}\left(M_0/M\right)$, where $M_0\simeq 2.8\,M_\odot$. For a few tens of events per year well into the Local Universe within 50-100Mpc, probes at the detector-limited sensitivity are expected to break the degeneracy between their NS or BH central engines {by GW calorimetry.