Supernovae powered by magnetars that transform into black holes

TL;DR

This paper models supernova light curves powered by magnetars that collapse into black holes, explaining rapid declines and bright transients observed in recent astronomical data.

Contribution

It introduces a new model for supernovae powered by magnetars that transform into black holes, capturing rapid light curve declines and shock breakout features.

Findings

Rapid post-maximum decline in light curves due to black hole formation

Enhanced shock breakout signals from magnetar-driven bubbles

Consistency with observed rapidly evolving bright transients

Abstract

Rapidly rotating, strongly magnetized neutron stars (magnetars) can release their enormous rotational energy via magnetic spin-down, providing a power source for bright transients such as superluminous supernovae. On the other hand, particularly massive (so-called supramassive) neutron stars require a minimum rotation rate to support their mass against gravitational collapse, below which the neutron star collapses to a black hole. We model the light curves of supernovae powered by magnetars which transform into black holes. Although the peak luminosities can reach high values in the range of superluminous supernovae, their post maximum light curves can decline very rapidly because of the sudden loss of the central energy input. Early black hole transformation also enhances the shock breakout signal from the magnetar-driven bubble relative to the main supernova peak. Our synthetic light curves of supernovae powered by magnetars transforming to black holes are consistent with those of some rapidly evolving bright transients recently reported by Arcavi et al. (2016).