Robust applicability of the τ-based spectrum parameterization beyond core-collapse supernovae

Determine whether the neutrino energy-spectrum parameterization based on the characteristic thermal-diffusion area τ(t) applies robustly outside core-collapse supernovae, specifically to non-CCSN sources such as neutrino spectra from neutron-star common-envelope systems and other low-average-energy regimes, by validating its performance against independent datasets beyond CCSNe.

Background

The paper introduces a physically motivated parameterization of supernova neutrino spectra in which the central parameter τ(t) quantifies a characteristic thermal-diffusion area. The method is validated on SN 1987A and a suite of 3D CCSN simulations, and a case study compares its fit to a low-average-energy spectrum from a neutron-star common-envelope scenario.

In these non-CCSN contexts, the authors find that both their method and the KRJ parameterization provide nearly identical, highly effective fits in the single case studied, but they emphasize that these are only case studies and thus insufficient to establish robust applicability beyond core-collapse supernovae. They also suggest exploring extensions to other transients such as novae, luminous red novae, and fast blue optical transients.