Speaker
Description
Core-collapse supernovae from rapidly rotating and strongly magnetised progenitors are promising candidates for producing the highly energetic hypernova explosions we observe in nature. Current theoretical hydrodynamical supernova simulations have yet to reproduce the same high energies beyond $10^{52}$ erg that we associate with the observed hypernova.
I will present four magnetohydrodynamical (MHD) core-collapse supernova simulations of 8, 13, 17, and 20 M$_{\odot}$ progenitors with initial magnetic fields of $10^{10}$ G. For each progenitor, we perform 2D and 3D simulations and follow the evolution for $<1$ s after core bounce, analysing the explosion, proto-neutron star (PNS), and shock-radius evolution. The explosion energies of all four 3D models asymptote to ranges between $5.51\times10^{50}$ and $1.83\times10^{51}$ erg. These exceed those obtained for non-rotating, non-magnetised progenitors of similar mass (Sykes and Müller, 2024), but remain below the $\sim10^{52}$ erg associated with hypernovae. I will discuss outflows and jets in all four 3D simulations, including nucleosynthesis within the outflows and the relative roles of magnetic and gas pressure. Several models exhibit enhanced magnetic pressure along the PNS polar axis, indicating magnetically driven jets.
Although hypernova-like energies are not achieved, PNS spin evolution shows invert advection of angular momentum increasing with time as hydrodynamic transport outweighs magnetic torques, implying an increasing reservoir of rotational energy (aligning with the proposed magnetar models) that could power more energetic explosions if efficiently extracted. Despite our explosions not exceeding $10^{52}$ erg, the additional reservoir of rotational energy enables our models to achieve explosion energies comparable to those found in simulations of progenitors more than twice as massive (Powell et al., 2023). Three of the four simulations also develop pronounced bipolar distributions of iron-group ejecta, consistent with asymmetric, jet-influenced explosion geometries.