Institut de recherche sur les lois fondamentales de l'Univers

Gamma-ray bursts (GRBs) are one of the most energetic explosions in the universe, and can be observed across a wide range of wavelengths (from radio to GeV). Therefore, GRBs provide a rich environment to study astrophysics and offer a unique probe of cosmology, particularly the early universe.

Swift, a multi-wavelength telescope dedicated to GRB study, marks its 10-year anniversary on Nov. 20, 2014. To date, the Burst Alert Telescope (BAT) onboard Swift has detected ~ 1000 gamma-ray bursts (GRBs), within which ~ 330 GRBs have redshift measurements, ranging from z=0.03 to z=9.38.

 
In this talk, I will present summaries of the GRB observations from the Swift/BAT and discuss potential selection effects from the instrument and the trigger algorithm. Furthermore, I will present our study on the GRB rate with simulations of the BAT trigger algorithm, and discuss its implications for the high-redshift star-formation history.