Constrain the occurrence fraction of Type II-P supernovae with dense, extended circumstellar media

Determine the fraction of core-collapse supernovae that are Type II-P events and possess sufficiently dense and extended circumstellar media for the predicted gamma-ray detectability conditions.

Background

The predicted gamma-ray detection rates depend on the fraction of core-collapse supernovae that are Type II-P events and on the fraction of Type II-P supernovae surrounded by circumstellar material that is both sufficiently dense to enhance hadronic gamma-ray production and sufficiently extended to sustain the emission. The paper treats these rates as conditional because the relevant population fractions are not currently well constrained.

References

In addition, the event rates relevant to the dense CSM cases depend on the fraction of core-collapse SNe that are Type~II-P SNe and on the occurrence fraction of Type~II-P SNe with sufficiently dense and extended CSM. These fractions are not well constrained at present.

— Detectability of 100 TeV Gamma Rays from PeV Cosmic Rays Accelerated in the Early Phase of a Supernova Shock Wave  (2609.18226 - Nishikawa et al., 16 Sep 2026) in Section Discussion