GCN Circular 4716
H. Terada, T.-S. Pyo (Subaru Telescope, NAOJ), N. Kobayashi (University of Tokyo) and N. Kawai (Tokyo Tech) report: "Near-infrared photometry of the afterglow of GRB 060206 (Morris et al., GCN #4682) in the J, K'-bands was performed with IRCS (Infrared Camera and Spectrograph) on the SUBARU Telescope at February 7.5 UT. An average seeing was 0.5 arcsec in the J-band and 0.3 arcsec in the K'-band. The magnitude of the afterglow was J=18.77 +/ -0.04 at 10:38-11:04 UT (t=30.1 hr) and K'=17.78 +/ -0.01 at 13:37-14:30 UT (t=33.3 hr). The near-infrared decay index of the afterglow is estimated to be -1.11 in the J-band and -1.22 in the K'-band from comparison with the earlier report (J=15.96 and Ks=14.54 at t=2.9 hr, GCN #4702)." This message may be cited.