Three approaches for the classification of protoneutron star oscillation modes

Understand

The future detection of gravitational waves (GWs) from a galactic core-collapse supernova will provide information on the physics inside protoneutron stars (PNS).

• In this work, we apply three different classification methods for the PNS non-radial oscillation modes: Cowling classification, Generalized Cowling Nomenclature (GCN), and a Classification Based on Modal Properties (CBMP).
• Using PNS models from $3$D simulations of core-collapse supernovae, we find that in the early stages of the PNS evolution, typically before $0.4$ seconds after the bounce, the Cowling classification is inconsistent, but the GCN and the CBMP provide complementary information that helps to understand the evolution of the modes.
• In the GCN, we note several avoided crossings as the mode frequencies evolve at early times, while the CBMP tracks the modes across the avoided crossings.