TITLE:   GCN CIRCULAR
NUMBER:  19125
SUBJECT: GRB 160227A: LOAO 1.0m optical detection
DATE:    16/03/01 09:07:13 GMT
FROM:    Soomin Jeong at IAA-CSIC  <sjeong@iaa.es>

Soomin Jeong (SKKU/IAA-CSIC), Myungshin Im (SNU), Yuji Urata (NCU), Il H. Park (SKKU) on behalf of a larger collaboration:

We observed the field of GRB 160227A (Siegel, et al., GCN 19098) with the 1m telescope of Mt. Lemmon Optical Astronomy Observatory (LOAO) in Arizona. 
The series of images are taken in R- & B-filter starting on Feb. 28 05:11:27 UT (~ 9.7 hr post burst). 
The optical counterpart is clearly detected in a median combined image of R at the previously reported optical afterglow position 
(e.g., Siegel et al., GCN 19098; Gorbovskoy et al., GCN 19099; Mazaeva et al., GCN19102). We confirmed marginal detection of OT in a median combined B. 
The observed magnitudes are as following:
Mid Time(hr)     Exposure(s)       Filter       Magnitude
———————————————————————————
10.19         12x300            R          21.16 +/- 0.14
10.15          4x300             B           22.19 +/- 0.41
———————————————————————————
The fields are calibrated to the near by star at RA=194.74877, Dec=78.68984 (R2=15.84, USNO-B1.0).