GRB 130925A: an ultra-long Gamma Ray Burst with a dust-echo afterglow, and implications for the origin of the ultra-long GRBs

P. A. Evans, R. Willingale, J. P. Osborne +24

GRB 130925A was an unusual GRB, consisting of 3 distinct episodes of high-energy emission spanning $\sim$20 ks, making it a member of the proposed category of `ultra-long' bursts.…