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 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