Critical angular momentum distributions in collapsars: quiescent periods from accretion state transitions in long gamma-ray bursts

Abstract

The rotation rate in pre-supernova cores is an important ingredient which can profoundly affect the post-collapse evolution and associated energy release in supernovae and long gamma ray bursts (LGRBs). Previous work has focused on whether the specific angular momentum is above or below the critical value required for the creation of a centrifugally supported disk around a black hole. Here, we explore the effect of the distribution of angular momentum with radius in the star, and show that qualitative transitions between high and low angular momentum flow, corresponding to high and low luminosity accretion states, can effectively be reflected in the energy output, leading to variability and the possibility of quiescent times in LGRBs.