Supernova Gamma-Ray Echo as an Astrophysical Near Detector for Galactic Neutrino Propagation
Abstract
Core-collapse supernova neutrinos offer a unique probe of physics beyond the Standard Model over Galactic baselines. Yet even a high-statistics nearby burst may be limited by source uncertainties, especially for propagation effects that average over energy and appear only as an overall flux suppression. Inspired by near--far comparisons in terrestrial oscillation experiments, we show that next-generation MeV observations of the supernova gamma-ray echo---the delayed 511 keV signal induced by the neutrino burst in the stellar envelope---can serve as an astrophysical near detector for the emitted ν̅e fluence. Comparing this echo-inferred source fluence with the surviving flux measured at Earth gives a direct test of neutrino propagation between the stellar surface and the detector. For pseudo-Dirac neutrinos, this turns the fully averaged active--sterile oscillation regime from an unobservable source-normalization ambiguity into a measurable near--far deficit, with sensitivity for nearby progenitors to splittings δm2≳ 10−18 eV2(0.22 kpc/D)(E⋆/15 MeV). The same near--far logic also applies to other propagation-induced modifications of the observed flux, including neutrino decay and neutrino interactions with Galactic dark matter.
Related
- Exploring neutrino loss with diffuse astrophysical neutrino fluxes
- Neutrino helicity oscillations in astrophysical environments: A many-body approach
- Constraining tau-sterile neutrino mixing with high-energy astrophysical neutrinos
- Charged-current neutrino opacity within the relativistic Hartree-Fock framework for astrophysical simulations of core-collapse supernovae and binary neutron star mergers
- Probing Scalar-Induced First-Order Phase Transitions with the Diffuse Supernova Neutrino Background
BibTeX
@misc{chauhan2026supernova,
title = {{Supernova Gamma-Ray Echo as an Astrophysical Near Detector for Galactic Neutrino Propagation}},
author = {Garv Chauhan and Yago Porto},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.26908},
eprint = {2609.26908},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.26908},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Supernova Gamma-Ray Echo as an Astrophysical Near Detector for Galactic Neutrino Propagation
AU - Garv Chauhan
AU - Yago Porto
PY - 2026
DA - 2026/09/22
PB - arXiv
DO - 10.48550/arxiv.2609.26908
UR - https://arxiv.org/abs/2609.26908
AB - Core-collapse supernova neutrinos offer a unique probe of physics beyond the Standard Model over Galactic baselines. Yet even a high-statistics nearby burst may be limited by source uncertainties, especially for propagation effects that average over energy and appear only as an overall flux suppression. Inspired by near--far comparisons in terrestrial oscillation experiments, we show that next-generation MeV observations of the supernova gamma-ray echo---the delayed 511 keV signal induced by the neutrino burst in the stellar envelope---can serve as an astrophysical near detector for the emitted ν̅_e fluence. Comparing this echo-inferred source fluence with the surviving flux measured at Earth gives a direct test of neutrino propagation between the stellar surface and the detector. For pseudo-Dirac neutrinos, this turns the fully averaged active--sterile oscillation regime from an unobservable source-normalization ambiguity into a measurable near--far deficit, with sensitivity for nearby progenitors to splittings δm^2≳ 10^−18 eV^2(0.22 kpc/D)(E_⋆/15 MeV). The same near--far logic also applies to other propagation-induced modifications of the observed flux, including neutrino decay and neutrino interactions with Galactic dark matter.
ER -