A Correlation Between Intrinsic Luminosity and Average Decay Rate in GRB Afterglows

Author: Judith Racusin

Abstract: We will present recent efforts to characterize and understand the origin of the correlation between the early luminosity of GRB afterglows and the rate at which they decay, discovered by Oates et al. 2012 in the UV/optical afterglows observed by Swift. The study has been expanded to the X-ray afterglows observed by Swift-XRT, which demonstrate more complex temporal structures than the optical light curves, reflecting contributions from multiple emission components, and find that the correlation is also significant in the X-ray. We explore in further detail whether the the origin of the correlation is geometrical - due to some component of the observing perspective, physical - an intrinsic property of the GRB jet, or an observing bias - that may explain some of the wide variation in GRB light curves.