Bibcode
Nicuesa Guelbenzu, A.; Klose, S.; Rossi, A.; Schmidl, S.; Greiner, J.; Kann, D. A.; Elliott, J.; Olivares E., F.; Rau, A.; Schady, P.; Sudilovsky, V.; Krühler, T.; Ferrero, P.; Schulze, S.; Afonso, P. M. J.; Filgas, R.; Nardini, M.
Referencia bibliográfica
EAS Publications Series, Volume 61, 2013, pp.325-330
Advertised on:
7
2013
Número de citas
0
Número de citas referidas
0
Descripción
We report on follow-up observations of 20 short-duration gamma-ray
bursts (T90 < 2s) performed in g'r'i'z'JHKs
with the Gamma-Ray Burst Optical Near-Infrared Detector (GROND) between
mid-2007 and the end of 2010. This is the most homogeneous and
comprehensive data set on GRB afterglow observations of short bursts. In
three cases, GROND was on target within less than 10 min after the
trigger, leading to the discovery of the afterglow of GRB 081226A and
its faint underlying host galaxy. In addition, GROND was able to image
the optical afterglow and follow the light curve evolution in five
further cases: GRBs 090305, 090426, 090510, 090927, and 100117A. Three
of the aforementioned six bursts with optical light curves show a break:
GRBs 090426 and 090510 as well as GRB 090305. For GRB 090927, no break
is seen in the optical/X-ray light curve until about 150 ks/600 ks after
the burst. A decay slope of the optical afterglow of GRB 100117A could
be measured. Using these data supplemented by about ten events taken
from the literature, we compare the jet half-opening angles of long and
short bursts. We find a tentative evidence that short bursts have wider
opening angles than long bursts. However, the statistics are still very
poor and follow-up observations of these events are therefore very
important to gain as much observational data as possible.