Fast time variations of supernova neutrino fluxes and their detectability

TL;DR

This paper investigates the detectability of rapid neutrino flux variations caused by hydrodynamic instabilities in supernovae, demonstrating that current and future large detectors can observe these signals to infer supernova core physics.

Contribution

It provides detailed analysis showing that fast neutrino flux variations from supernovae are detectable with IceCube and similar detectors, linking these observations to supernova explosion mechanisms.

Findings

Fast neutrino flux variations are detectable with IceCube.

Hydrodynamical simulations predict large amplitude variations up to hundreds of Hz.

Detection can reveal information about supernova core physics.

Abstract

In the delayed explosion scenario of core-collapse supernovae (SNe), the accretion phase shows pronounced convective overturns and a low-multipole hydrodynamic instability, the standing accretion shock instability (SASI). These effects imprint detectable fast time variations on the emerging neutrino flux. Among existing detectors, IceCube is best suited to this task, providing an event rate of ~1000 events per ms during the accretion phase for a fiducial SN distance of 10 kpc, comparable to what could be achieved with a megaton water Cherenkov detector. If the SASI activity lasts for several hundred ms, a Fourier component with an amplitude of 1% of the average signal clearly sticks out from the shot noise. We analyze in detail the output of axially symmetric hydrodynamical simulations that predict much larger amplitudes up to frequencies of a few hundred Hz. If these models are roughly representative for realistic SNe, fast time variations of the neutrino signal are easily detectable in IceCube or future megaton-class instruments. We also discuss the information that could be deduced from such a measurement about the physics in the SN core and the explosion mechanism of the SN.