Using Gamma Ray Monitoring to Avoid Missing the Next Milky Way Type Ia Supernova

Abstract

A Milky-Way Type Ia Supernova (SNIa) could be unidentified or even initially unnoticed, being dim in radio, X-rays, and neutrinos, and suffering large optical/IR extinction in the Galactic plane. But SNIa emit nuclear gamma-ray lines from 56 Ni → 56 Co → 56 Fe radioactive decays. These lines fall within the Fermi/GBM energy range, and the 56 Ni 158 keV line is detectable by Swift/BAT. Both instruments frequently monitor the Galactic plane, which is transparent to gamma rays. Thus GBM and BAT are ideal Galactic SNIa early warning systems. We simulate SNIa MeV light curves and spectra to show that GBM and BAT could confirm a Galactic SNIa explosion, followed by Swift localization and observation in X-rays and UVOIR band. The time of detection depends sensitively on the 56 Ni distribution, and can be as early as a few days if > ∼ 10% of the 56 Ni is present in the surface as suggested by SN2014J gamma data.

Exciting Prospects for Detecting Late-Time Neutrinos from Core-Collapse Supernovae

“…In addition to ASAS-SN, a wide variety of telescopes across the full electromagnetic spectrum would certainly be quickly marshaled to search for the supernova. Many bands are insensitive to extinction by dust, and some can be used even in directions near the Sun (e.g., MeV gamma rays [194]). In many bands, the supernova will remain detectable for months or even years [195,196], allowing a wide range of techniques for estimating distances to be used [1].…”