[vsnet-grb-info 17660] GRB 160225A: LOAO optical upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19097
SUBJECT: GRB 160225A: LOAO optical upper limit
DATE:    16/02/27 12:16:10 GMT
FROM:    Soomin Jeong at IAA-CSIC  <sjeong at iaa.es>

S. Jeong (SKKU/IAA-CSIC), M. Im (SNU), Y. Urata (NCU), I. H. Park (SKKU) on behalf of larger collaboration:

We observed the field of GRB 160225A (Siegel, et al., GCN 19075) with the 1m telescope of Mt. Lemmon Optical Astronomy Observatory (LOAO) in Arizona. 
The series of images are taken in R filter starting on Feb. 26 02:45:36 UT (~12.4 hr post burst). We do not detect any optical afterglow candidate within the 
XRT enhanced error circle (Goad et al., GCN 19077) down to the following magnitudes calibrated with the nearby USNO-B1.0 stars. The non-detection is consistent with 
the previous UL report in similar epoch (Butler, et al., GCN 19088). 
Mid Time      Exposure       Filter       Magnitude
(hr)           (s)
-------------------------------------------------------
12.83         9x300            R          > 21.5
-------------------------------------------------------
USNO-B1.0_id   R1    R2       
1436-0208445 14.73 15.26  14.995
1436-0208447 13.55 13.74  13.645