[vsnet-grb-info 18163] GRB 160625B: SAO RAS optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19611
SUBJECT: GRB 160625B: SAO RAS optical observations
DATE:    16/06/28 14:00:13 GMT
FROM:    Moskvitin Alexander at SAO RAS  <mosk at sao.ru>

A. Moskvitin (SAO RAS, Russia) report on behalf of the larger team.

After fruitful multiband observations of the GRB 160625B optical
counterpart by several telescopes including Mini-MegaTORTORA
system located at SAO RAS (Karpov et al. GCNC #19603)
we observed the GRB160625B field (Dirirsa et al. GCNC #19580)
with the 1-meter telescope Zeiss-1000 of SAO RAS on June, 27.923
(1.976 days after the trigger). 7 x 300 sec. images in Rc band
were obtained under good weather conditions.

The OT is clearly visible in separate frames and in the stacked frame.
It's position is perfectly consistent with the coordinates reported by
Troja et al. (GCNC #19588) and Alexander et al. (GCNC #19606).
During our observations the OT magnitude was R = 19.87 +/- 0.07.
This estimation is based on the R2 magnitudes of nearby USNO-B1 stars,
without any correction for the Galactic extinction in the GRB direction.
The finding chart can be found at
ftp://ftp.sao.ru/pub/grb/GRB160625B/GRB160625B_z1000.jpg