TITLE: GCN CIRCULAR NUMBER: 17691 SUBJECT: GRB 150413A: MAXI/GSC detection DATE: 15/04/13 15:09:31 GMT FROM: Motoko Suzuki at RIKEN M. Serino (RIKEN), H. Negoro (Nihon U.), S. Nakahira (JAXA), S. Ueno, H. Tomida, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), N. Kawai, T. Yoshii, Y. Tachibana (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, R. Imatani (Osaka U.), M. Nakajima, T. Namba, M. Fujita, F. Honda, K. Tanaka, T. Masumitsu (Nihon U.), Y. Ueda, T. Kawamuro, T. Hori (Kyoto U.), Y. Tsuboi, S. Kanetou (Chuo U.), M. Yamauchi, D. Itoh (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Morii (ISM) report on behalf of the MAXI team: At 13:56:30 UT, the MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at the position (R.A., Dec) = (190.278 deg, 71.742 deg) = (12 41 07, +71 44 31) (J2000). The position is consistent with that reported by Markwardt et al. (GCN 17688). The X-ray flux averaged over the scan was 440 +- 40 mCrab (4-10keV, 1 sigma error). There was no significant excess flux in the previous transit at UT 12:24 with an upper limit of 20 mCrab.