RSAA Colloquia / Seminars / Feast-of-Facts: Thursday, 19 February 2015, 11:00-12:00; Duffield Lecture Theatre

Antonia Rowlinson

"Constraining the progenitor and central engine of short GRBs"

After being first recognised as a distinct category of Gamma-Ray Bursts (GRBs), the progenitors of short GRBs have remained highly elusive although we have long suspected that they are compact binary mergers. Electromagnetic counterparts of Short GRBs are typically faint and rapidly fade below detection thresholds, making them notoriously difficult to study. In 2013, the first "smoking gun" detection was made, providing strong evidence that the net is finally closing in on the progenitors of short GRBs. In the coming years, if there is a joint detection of a short GRB and a gravitational wave burst by Advanced LIGO, this progenitor theory will be confirmed. The compact binary merger progenitor is typically thought to produce a black hole central engine. However, we have now identified prolonged energy injection in short GRB lightcurves that is inconsistent with the expected black hole central engine. In this talk, I will summarise the observational constraints on the progenitors of short GRBs and describe an alternative central engine model, a millisecond magnetar, that is capable of explaining the prolonged energy injection that we observe.