Dr Amit Kumar (Royal Holloway, University of London)

Supernovae (SNe) and gamma-ray bursts (GRBs) represent some of the most powerful and luminous explosions in the Universe, with growing evidence linking these two classes of transients, particularly long GRBs (LGRBs) and broad-lined stripped-envelope SNe (Ic-BL SESNe). To date, over fifty LGRBs have been observed with associated supernovae (GRB-SNe), showing characteristic late-time re-brightening in GRBs' afterglows and broad spectral features. Millisecond magnetars—ultra-magnetized, rapidly spinning neutron stars formed in the collapse of massive stars—are proposed as possible powering sources behind these explosive events. Acting as central engines, magnetars inject immense energy into their surroundings, driving the diverse observational features of both LGRBs and SESNe. The magnetar-driven model provides a compelling framework to explain the diversity observed among these explosive events: by varying initial spin periods, magnetic field strengths, and central engine activity durations, magnetars can produce different transient behaviours. Faster-spinning, stronger-field magnetars might yield the intense, short-lived emissions characteristic of GRBs, while others may power slower, more sustained light curves in SNe.

In my talk I will discuss the connections between SNe and GRBs and millisecond magnetars are their possible powering sources. The talk will also cover the topic of how variations in magnetar properties shape these cataclysmic events. Such insights enhance our understanding of stellar death and the life cycles of massive stars, shedding light on the extreme physics driving some of the most luminous phenomena in the cosmos.

Image Credit: NASA Goddard