[vsnet-grb-info 6670] GRB 080916C: GROND Confirmation of the Optical Afterglow

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8273
SUBJECT: GRB 080916C: GROND Confirmation of the Optical Afterglow
DATE:    08/09/19 10:08:07 GMT
FROM:    Christian Clemens at MPE  <cclemens at mpe.mpg.de>

C. Clemens (MPE Garching), A. Rossi (Tautenburg Obs.), J. Greiner, S. McBreen, 
T. Kruehler, A. Yoldas (all MPE Garching), A. Kupcu Yoldas (ESO) and G. 
Szokoly (Eoetvoes Univ., Budapest) report on behalf of the GROND team:

We observed the field of GRB 080916C for a second time with GROND at 08:04 UT 
on September 19th, 2008, 3.3 d after the GBM trigger with 54 min of effective 
exposures. Observations were performed at an average seeing of 1.7" and at an 
average airmass of 1.7.

We do not detect the afterglow candidate first reported by Clemens et al. (GCN 
#8257) with the following 5-sigma upper limits:

z' > 22.7 mag.

These measurements strongly indicate a fading of the source compared to our 
first epoch observations. We therefore propose this is to be the afterglow of 
GRB 080916C.