GRB 230307A was an exceptionally bright long-duration gamma-ray burst first detected by the Fermi Gamma-ray Burst Monitor on 7 March. Such events are usually understood to arise from the supernova of a massive star; unexpectedly, optical followup indicated behaviour similar to a kilonova, until now associated with short-duration bursts (which are thought to arise instead from compact object mergers, like the famous GW170817).

Andrew Levan and collaborators carried out extensive optical imaging and spectroscopy following the event, which I played an infinitessimally small role in. Most excitingly, the campaign also found a spectral line feature in JWST mid-IR spectrum, possibly arising from Tellurium produced (presumably along with other heavy elements) during the event. The paper has now been accepted by Nature and is also available at arXiv:2307.02098.

Labels: 2023, transients