TITLE: GCN CIRCULAR NUMBER: 16778 SUBJECT: GRB 140903A: MAXI/GSC upper limit DATE: 14/09/05 03:31:00 GMT FROM: Motoko Suzuki at RIKEN M. Serino (RIKEN), T. Sakamoto (AGU), N. Kawai (Tokyo Tech), S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Morii, J. Sugimoto, T. Takagi, A. Yoshikawa, M. Matsuoka (RIKEN), T. Yoshii, Y. Tachibana (Tokyo Tech), A. Yoshida, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, D. Uchida (Osaka U.), H. Negoro, M. Nakajima, K. Fukushima, T. Onodera, K. Suzuki, T. Namba, M. Fujita, F. Honda (Nihon U.), Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, A. Kawagoe (Chuo U.), M. Yamauchi, Y. Morooka, D. Itoh (Miyazaki U.), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team: The MAXI/GSC scanned the field of GRB 140903A triggered by Swift BAT (Cumming et al. GCN Circ. 16763) at 15:00:42 (12 sec after the trigger) UT on 2014-09-03. The durations of the scan was 44 sec. No obvious source was detected by MAXI/GSC at the location of BAT. The 3 sigma upper limit of the scan derived by the MAXI/GSC data is 8.4 x 10^-10 erg/cm2/s (4-10 keV). This upper limit is roughly consistent with the power-law interpolation of the BAT prompt emission flux (T ~ 0-0.3 s) and the first XRT point (t ~ 100 s), assuming that the BAT spectrum (power-law with photon index 1.99, Palmer et al. GCN Circ. 16768) extends down to soft X-ray emission with no spectral break. It suggests that no strong soft extended emission was associated with this GRB (Sakamoto et al. GCN Circ. 16771).