event ratio should be observed. Therefore, the time variation of the event number ratio is useful to investigate the effect of the RSF conversion.'
author:
- Takashi Yoshida$^1$
- Akira Takamura$^2$
- Keiichi Kimura$^3$
- Hidekazu Yokomakura$^3$
- Shio Kawagoe$^4$
- 'Toshitaka Kajino$^{1,5}$'
title: |
    Resonant Spin-Flavor Conversion of Supernova Neutrinos:\
    Dependence on Electron Mole Fraction
---

\[sec:level1\]Introduction
==========================

Core-collapse supernovae (SNe) supply a huge amount of neutrinos $(N_\nu \sim 10^{58})$ in a time scale of $\sim 10$ s. If one SN explodes in our Galaxy, thousands of neutrinos are expected to be detected by 10 kton size neutrino detectors. The energy spectra of SN neutrinos will provide various information of SN explosion mechanism as well as neutrino oscillation parameters. SN neutrinos are emitted from proto-neutron stars, where the density is much larger than the density of higher resonance of the Mikheyev-Smirnov-Wolfstein (MSW) effect. The energy spectra and the dependence on neutrino oscillation parameters are quite different from solar neutrinos (e.g., [@ds00]). Therefore, the neutrinos released from SNe in our Galaxy will supply fruitful information on neutrino physics and astrophysics.

Although the magnetic moment of neutrinos is considered to be \`\`very small,” a finite magnetic moment may affect astrophysical phenomena 