Identifying rotation in SASI-dominated core-collapse supernovae with a neutrino gyroscope

TL;DR

This paper proposes using neutrino signals as stellar gyroscopes to detect and analyze the rotation of core-collapse supernovae, revealing rotational effects on neutrino emission patterns through 3D simulations.

Contribution

It demonstrates that neutrino emission properties can reveal the rotation of supernovae, especially through SASI activity signatures in spectrograms, using detailed 3D simulation comparisons.

Findings

Rotating supernova models show broad frequency activity in neutrino signals.

Spectrograms of rotating models display secondary peaks at higher frequencies.

Detectable rotational imprints in neutrino signals are possible for supernovae within 10 kpc.

Abstract

Measuring the rotation of core-collapse supernovae (SN) and of their progenitor stars is extremely challenging. Here it is demonstrated that neutrinos may potentially be employed as stellar gyroscopes, if phases of activity by the standing accretion-shock instability (SASI) affect the neutrino emission prior to the onset of the SN explosion. This is shown by comparing the neutrino emission properties of self-consistent, three-dimensional (3D) SN simulations of a 15 M_sun progenitor without rotation as well as slow and fast rotation compatible with observational constraints. The explosion of the fast rotating model gives rise to long-lasting, massive polar accretion downflows with stochastic time-variability, detectable e.g. by the IceCube Neutrino Observatory for any observer direction. While spectrograms of the neutrino event rate of non-rotating SNe feature a well-known sharp peak due to SASI for observers located in the proximity of the SASI plane, the corresponding spectrograms of rotating models show activity over a wide range of frequencies, most notably above 200 Hz for rapid rotation. In addition, the Fourier power spectra of the event rate for rotating models exhibit a SASI peak with lower power than in non-rotating models. The spectra for the rotating models also show secondary peaks at higher frequencies with greater relative heights compared to the main SASI peak than for non-rotating cases. These rotational imprints will be detectable for SNe at 10 kpc or closer.