TITLE:   GCN CIRCULAR
NUMBER:  17240
SUBJECT: GRB 141225A: very early T60 observations
DATE:    14/12/26 16:15:01 GMT
FROM:    Eda Sonbas at NASA/GSFC  <edasonbas@gmail.com>

E. Sonbas (Adiyaman Univ.), T. Guver (Istanbul Univ.), E. Gogus (Sabanci
Univ.), M. Parmaksizoglu, M. Dindar, H. Kirbiyik (TUG) report on behalf of
a larger collaboration


 We observed the field of Swift GRB 141225A (D'Avanzo et al., GCN#17229)
with the 0.60 meter robotic T60 telescope (Dindar et al. 2014; Bakirlitepe,
TUBITAK National Observatory, Turkey), starting December, 25, 23:03:16.37
UT (~ 129 second after the trigger). Observations were carried out with the
R and B filters. The afterglow (Gorosabel et al., GCN 17230; Guidorzi et
al., GCN 17231; Malesani et al., GCN 17232; Kuin & D'Avanzo, GCN 17233, Xu
et al. GCN 17236, Buckley et al. GCN 17237) is clearly detected in the R
band images with an exposure time of 60 s.


Using USNO-B1 star USNO-B1 1237-0186662 (R.A.=138.789, Dec=+33.797) in the
field, the R magnitudes of the OT were estimated as follows;


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

~129 60 R 17.04 0.04

~195 60 R 17.15 0.02


Further analysis are ongoing.


We are grateful to TUBITAK National Observatory for a partial support in
using T60 telescope with project number 539 and technical support.