TITLE:   GCN CIRCULAR
NUMBER:  18518
SUBJECT: GRB 151027A: T100 observations
DATE:    15/10/28 17:37:17 GMT
FROM:    Eda Sonbas at NASA/GSFC  <edasonbas@gmail.com>

E. Sonbas (Adiyaman Univ.), T. Guver (Istanbul Univ.), E. Gogus (Sabanci
Univ.), O. Erece, M. Kocak, S. Eryilmaz, H. Kirbiyik (TUG) report on behalf
of a larger collaboration


We observed the field of Swift GRB 151027A (Maselli et al., GCN#18478) with
the 1.0 meter T100 telescope (Bakirlitepe, TUBITAK National Observatory,
Turkey), starting October, 27, 18:32:21 UT (~ 14.5 hours after the
trigger). Observations were carried out in the R filter. The afterglow is
detected in the R band images with an exposure time of 150 s.


Using USNO-B1 star USNO-B1 1513-0237223 (R.A.=272.49, Dec=+61.37) in the
field, the magnitudes of the OT were estimated as follows;


t-t0 (hr) exp.(s) filt mag err (+/-)

14.56 150 R 16.8 0.06

14.61 150 R 17.2 0.08


Analysis of further observations with the same filter is ongoing.


We thank to TUBITAK National Observatory for a partial support in using
T100 telescope with project number 10CT100-95 and technical support.