One of the open questions following the discovery of GW170817 is whether neutron star (NS) mergers are the only astrophysical sites capable of producing r-process elements. Simulations have shown that 0.01–0.1 M $_ødot$ of r-process material could be …
We report observations of the optical counterpart of the long gamma-ray burst (GRB) GRB 230812B and its associated supernova (SN) SN 2023pel. The proximity (z = 0.36) and high energy (E $_ γ,iso$ åisebox-0.5ex 10$^53$ erg) make it an important event …
The Zwicky Transient Facility (ZTF) performs a systematic neutrino follow-up programme, searching for optical counterparts to high- energy neutrinos with dedicated Target-of-Opportunity (ToO) observations. Since first light in March 2018, ZTF has …
Dirty fireballs are a hypothesized class of relativistic massive-star explosions with an initial Lorentz factor Γ$_init$ below the Γ$_init$ åisebox-0.5ex 100 required to produce a long-duration gamma-ray burst (LGRB), but which could still produce …
The Fermi Gamma-ray Burst Monitor (GBM) triggers on-board in response to åisebox-0.5ex 40 short gamma-ray bursts (SGRBs) per year; however, their large localization regions have made the search for optical counterparts a challenging endeavour. We …
The transition from prompt to afterglow emission is one of the most exciting and least understood phases in gamma-ray bursts (GRBs). Correlations among optical, X-ray, and gamma-ray emission in GRBs have been explored, to attempt to answer whether …
The early optical emission of gamma-ray bursts (GRBs) gives an opportunity to understand the central engine and first stages of these events. About 30% of GRBs present flares whose origin is still a subject of discussion. We present optical …
The epochs of origin of the first stars and galaxies, and subsequent growth of the first supermassive black holes, are among the most fundamental questions. Observations of the highest redshift Gamma-Ray Bursts (GRBs) will be the most compelling in …
We show that several GRB correlations have common features indicative of an origin in selection effects. We focus on the possible origin of the Epk-Eiso correlation in Swift data due to detector threshold truncation. The existence of faint Swift …
From Galactic binary sources, to extragalactic magnetized neutron stars, to long-duration GRBs without associated supernovae, the types of sources we now believe capable of producing bursts of gamma- rays continues to grow apace. With this emergent …