GCN Circular 5522
K. Aoki, I. Tanaka (Subaru Telescope, NAOJ) and N. Kawai (Tokyo Tech) report on behalf of the Subaru GRB team: "We began observing the field of GRB 060904A (Grupe et al., GCN 5502) with MOIRCS on the 8.2m Subaru Telescope at ~6 UT (5 hours after the burst). In the stacked image of the 18 x 120 sec exposure (mid time UT 6:24) in Ks band, we detected an object with 20.2 mag in the XRT error circle, though the object may be extended. In the the J band image of 21 x 120 sec exposure (mid time UT 7:13), we did not detect an object brighter than 21.0 mag in the XRT error circle. The magnitudes were estimated based on the 2 MASS objects in the field."