Neutrino and electromagnetic signatures from Superluminous Supernovae: a case study for SN 2017egm

Superluminous supernovae (SLSNe) are rare transients that are $\sim 10 - 100$ times more luminous than ordinary stellar explosions, reaching peak optical luminosities $\sim 10^{44} - 10^{45}$ erg s$^{-1}$. The energy source powering SLSNe remains uncertain. In this work, we explore the multi-wavelength and multi-messenger signatures of the scenario in which SLSNe are powered by a newly born millisecond magnetar. We model the dynamical evolution and emission from the coupled system comprised of the magnetar, wind, nebula, and supernova ejecta, consistently evaluating the pair multiplicity of the wind and nebula regions, and the bulk wind Lorentz factor governing the $e^+ - e^-$ injection spectra in the nebula. We compute the thermal and non-thermal electromagnetic signatures, neutrino signatures, and investigate their detection prospects. For SN 2017egm, the nearest observed SLSNe, our prediction for high-energy gamma rays matches the recent detection by Fermi LAT. For neutrinos, using SN 2017egm a canonical SLSNe, we find that in the era of the Vera C. Rubin Observatory, a stacking analysis with upcoming neutrino observatories can lead to $3\sigma$ detection significance of neutrino events from a population of SLSNe within a decade of operation.