TITLE:   GCN CIRCULAR
NUMBER:  15161
SUBJECT: GRB 130831A: T100 observations
DATE:    13/09/01 19:05:58 GMT
FROM:    Eda Sonbas at NASA/GSFC  <edasonbas@gmail.com>

E. Sonbas (Adiyaman Univ.), U. Temiz (Cukurova Univ.), T. Guver (Sabanci
Univ.), Z. Eker (Akdeniz Univ.), S. Kaynar (TUG), E. Gogus (Sabanci Univ.),
H. Kirbiyik (TUG)  report on behalf of a larger collaboration

We observed the field of Swift  GRB 130831A (Hagen et al. GCN#15139)
with  the  1.0 meter  T100  telescope  (TUBITAK National  Observatory,
Antalya - Turkey),  starting August, 31; 18:27:23 UT (~ 5.4 hours after
the trigger). Observations were carried out in the R filter under moderate
weather conditions. We detected a new source in 300 s R band
image at a position that is consistent with Swift/UVOT (Hagen et al.
GCN#15139)
Using USNO-B1 star USNO-B1 1193-0589854  (RA=  23:54:29.226, Dec=
+29:23:08.41) in the field, the magnitude of the OT were estimated as;

t-t0 (hr)         exp.(s)      filt            mag             err (+/-)
5.38               300           R           17.98             0.034
5.48               300           R           17.99             0.035

Further observations using the same filter are ongoing.

We are grateful to the TUBITAK National Observatory staff for promptly
scheduling the observations and their technical support.