TITLE: GCN CIRCULAR NUMBER: 9931 SUBJECT: GRB090904B : IRSF NIR upper limit DATE: 09/09/25 02:00:32 GMT FROM: Kenta Nishimoto at Nagoya U/MOA-II K. Nishimoto, T. Sako(Nagoya Univ.) on behalf of the MOA Collaboration, M. Kurita on behalf of the IRSF Collabration, T. Yosikawa(Kyoto Univ.), T. Suenaga(Soken Univ.) report: We searched for a NIR afterglow of GRB090904B (GCN9881, V. D'Elia et al.) starting from 17:6:57.7 UT on 2009 Sep 4 (15.71 hours after the burst) with the SIRIUS on the IRSF 1.4m telescope at SAAO in South Africa. In images of a 300sec exposure with J, H and Ks filter, we did not find any object except the reported star (GCN9882, Covino et al and GCN9892, Nishimoto et al.) within the error circle of the Swift XRT source position (GCN9887, J.P. Osborne et al.). Quick estimation of the limiting magnitude calibrated by using 2MASS catalog: J > 17.14 H > 16.57 K > 15.79