TITLE: GCN CIRCULAR NUMBER: 20672 SUBJECT: GRB 170208A: IRSF upper limits DATE: 17/02/14 07:27:20 GMT FROM: Katsuhiro L. Murata at Nagoya U K. L. Murata (Nagoya U), L. Townsend (UCT), I. Monageng (SAAO), Y. Moritani (Kavli IPMU), M. Jian (U of Tokyo), S. Chimasu (Tokai U), A. Kawachi (Tokai U), A. Okazaki (Hokkai-Gakuen U) and T. Nagayama (Kagoshima U) We observed the field of GRB 170208A (Cholden-Brown et al., GCN Circular #20631) with the near-infrared (J, H, Ks) simultaneous imaging camera SIRIUS attached to 1.4 m telescope IRSF (InfraRed Survey Facility) in Sutherland observatory, South Africa. The observations started on 2017-02-08 18:56:55 UT (~ 43 min. after the burst). We could not detect the afterglow within the enhanced XRT error circle (Evans et al., GCN Circular #20634) in the three bands. We have obtained the following preliminary upper limits (Vega magnitude system): J > 16.50 H > 16.25 Ks > 15.92 Given magnitudes were calibrated against 2MASS point sources in this field. The upper limits were determined as the magnitudes of the faintest star within 1 arcmin from the enhanced XRT position. This observation was carried out by IRSF and OISTER collaboration.