Giant Shells and Stellar Arcs as Relics of Gamma Ray Burst Explosions
  Gamma Ray Burst (GRB) explosions are powerful and frequent enough to make kiloparsec-size shells and holes in the interstellar media of spiral galaxies. The observations of such remnants are summarized. Several observed shells contain no obvious central star clusters and could be GRB remnants, but sufficiently old clusters that could have formed them by supernovae and winds might be hard to detect. 
Y.N. Efremov (1), B.G. Elmegreen (2), P.W. Hodge (3) ((1) MSU, Moscow   (2) IBM Watson, NY (3) U Washington, Seattle)