Paper detail

Magnetorotational core collapse of possible GRB progenitors. IV. A wider range of progenitors

The final collapse of the cores of massive stars can lead to a wide variety of outcomes in terms of electromagnetic and kinetic energies, nucleosynthesis, and remnants. The connection of this wide spectrum of explosion and remnant types to the properties of the progenitors remains an open issue. Rotation and magnetic fields in Wolf-Rayet stars of subsolar metallicity may explain extreme events such as superluminous supernovae and gamma-ray bursts powered by proto-magnetars or collapsars. Continuing numerical studies of magnetorotational core collapse including detailed neutrino physics, we focus on progenitors with zero-age main-sequence masses in the range between 5 and 39 solar masses. The pre-collapse stars are one dimensional models employing prescriptions for the effects of rotation and magnetic fields. Eight of the ten stars we consider being the results of chemically homogeneous evolution due to enhanced rotational mixing (Aguilera-Dena et al. 2018). All but one of them produce explosions driven by neutrino heating (more likely for low mass progenitors up to 8 solar masses) and non-spherical flows or by magnetorotational stresses (more frequent above 26 solar masses). In most of them and for the one non-exploding model, ongoing accretion leads to black-hole formation. Rapid rotation makes a subsequent collapsar activity plausible. Models not forming black holes show proto-magnetar driven jets. Conditions for the formation of nickel are more favourable in magneto-rotationally driven models, though our rough estimates fall short of the requirements for extremely bright events if these are powered by radioactive decay. However, approximate light curves of our models suggest that a proto-magnetar or black hole spin-down may fuel luminous transients (with peak luminosities ~ 10^{43...44} erg).