TAP Colloquium - Dr. Nicole Lloyd-Ronning
Gamma-ray Bursts: Inside and Out
Dr. Nicole Lloyd-Ronning
Los Alamos National Laboratory
More than twenty years after the discovery of the first gamma-ray burst (GRB) afterglow and the definitive determination of their cosmological distances, there are still a number of unsolved, fundamental questions related to the central engines and progenitor systems that produce GRBs. Although we have some constraints on necessary progenitor properties from GRB energetics, timescales, locations in their host galaxies, and other observables, there is still room for a vast zoo of single and binary star progenitors to explain these enigmatic events. In this talk, I will present recent results that offer constraints on gamma-ray burst progenitors, both in the context of their inner engine and their surrounding environments. In addition, I will discuss how the GRB jet opening angle appears to evolve over cosmic time, with GRB jets at high redshift more narrowly beamed than those at low redshift. I will show how this result can not only be used to learn about the nature of the beast behind these most powerful explosions in the universe but also offer constraints on the high redshift star formation rate.